ABCMdb

ABCA4 p.Ala1038Val

ClinVar:	c.3113C>T , p.Ala1038Val D , Pathogenic
Predicted by SNAP2:	C: N (82%), D: N (72%), E: N (78%), F: N (72%), G: N (87%), H: N (87%), I: N (66%), K: N (82%), L: N (82%), M: N (87%), N: N (87%), P: N (78%), Q: D (75%), R: N (78%), S: N (93%), T: N (93%), V: N (82%), W: D (53%), Y: N (78%),
Predicted by PROVEAN:	C: N, D: D, E: D, F: D, G: D, H: D, I: N, K: D, L: N, M: N, N: D, P: D, Q: D, R: D, S: N, T: N, V: N, W: D, Y: D,

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[hide] Ubiquitin-mediated proteasomal degradation of ABC ... J Pharm Sci. 2011 Sep;100(9):3602-19. doi: 10.1002/jps.22615. Epub 2011 May 12. Nakagawa H, Toyoda Y, Wakabayashi-Nakao K, Tamaki H, Osumi M, Ishikawa T
Ubiquitin-mediated proteasomal degradation of ABC transporters: a new aspect of genetic polymorphisms and clinical impacts.
J Pharm Sci. 2011 Sep;100(9):3602-19. doi: 10.1002/jps.22615. Epub 2011 May 12., [PMID:21567408]

Abstract [show]
The interindividual variation in the rate of drug metabolism and disposition has been known for many years. Pharmacogenomics dealing with heredity and response to drugs is a part of science that attempts to explain variability of drug responses and to search for the genetic basis of such variations or differences. Genetic polymorphisms of drug metabolizing enzymes and drug transporters have been found to play a significant role in the patients' responses to medication. Accumulating evidence demonstrates that certain nonsynonymous polymorphisms have great impacts on the protein stability and degradation, as well as the function of drug metabolizing enzymes and transporters. The aim of this review article is to address a new aspect of protein quality control in the endoplasmic reticulum and to present examples regarding the impact of nonsynonymous single-nucleotide polymorphisms on the protein stability of thiopurine S-methyltransferase as well as ATP-binding cassette (ABC) transporters including ABCC4, cystic fibrosis transmembrane conductance regulator (CFTR, ABCC7), ABCC11, and ABCG2. Furthermore, we will discuss the molecular mechanisms underlying posttranslational modifications (intramolecular and intermolecular disulfide bond formation and N-linked glycosylation) and ubiquitin-mediated proteasomal degradation of ABCG2, one of the major drug transporter proteins in humans.

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155 Effect of Mutations and Nonsynonymous SNPs on Protein Trafficking, Maturation, or ERAD of ABC Transporters Protein AA Mutation/SNP Effect on Protein Reference ABCA1 W590S Mutation Functional defect 115 R587W Mutation Impaired glycol processing 115 Q597R Mutation Impaired glycol processing, ERAD 115,116 Y1532C Mutation Altered protein trafficking 117 R1925Q Mutation Altered protein trafficking 118 ABCA3 R43L Mutation Altered protein trafficking 119 L101P Mutation Altered protein trafficking 119 R280C Mutation Altered protein trafficking 119 ABCA4 L541P Mutation Mislocalization 120 R602W Mutation Mislocalization 120 A1038V Mutation Mislocalization 120 C1490Y Mutation Mislocalization 120 ABCB1a G268V Mutation ERAD 121 G341C Mutation ERAD 121 I1196S Mutation Reduced glycosylation 122 ABCB4 I541F Mutation Accumulation in ER 123 ABCB11a E135K Mutation Reduced level of mature protein 124 L198P Mutation Reduced level of mature protein 124 E297G Mutation Reduced level of mature protein 124 L413W Mutation Reduced level of mature protein 124 R432T Mutation Reduced level of mature protein 124 D482G Mutation Immature protein in ER 124,125 N490D Mutation Reduced level of mature protein 124 A570T Mutation Reduced level of mature protein 124 T655I Mutation Reduced level of mature protein 124 Y818F SNP Moderate reduction of protein 124 G982R Mutation Retention in ER 125 R1153C Mutation ERAD 125 R1286Q Mutation Retention in ER 125 ABCC2a R768W Mutation Impaired protein trafficking 126 I1173F Mutation Impaired protein maturation 127 R1392 Mutation Impaired protein maturation 128 M1393 Mutation Impaired protein maturation 129 ABCC4a E757K SNP Altered protein trafficking 23 ABCC7 F508 Mutation Misfolding, ERAD 36-39,130 G85E Mutation Impaired protein maturation 130-132 G91R Mutation Impaired protein maturation 130-132 N1303K Mutation Impaired protein maturation 130-132 ABCC8 WT Wild type Ubiquitin-proteasome degradation 133 A116P Mutation Ubiquitin-proteasome degradation 133 V187D Mutation Ubiquitin-proteasome degradation 133 F1388 Mutation Impaired protein trafficking 134 L1544P Mutation Impaired protein trafficking 135,136 ABCC11a G180R SNP Ubiquitin-proteasome degradation 50 27 Mutation Ubiquitin-proteasome degradation 50 ABCG2a V12M SNP Altered protein localization 96 Q141K SNP Ubiquitin-proteasome degradation 102 F208S SNP Ubiquitin-proteasome degradation 78,99 S441N SNP Ubiquitin-proteasome degradation 78,99 Mutations of ABCA1, ABCA3, ABCA4, ABCB4, ABCB11, ABCC2, ABCC7 (CFTR), and ABCC8 are associated with Tangier disease, fatal surfactant deficiency, Stargardt disease, progressive familial intrahepatic cholestasis type 3 (PFIC-3), progressive familial intrahepatic cholestasis type 2 (PFIC-2), Dubin-Johnson syndrome, cystic fibrosis, and familial hyperinsulinism, respectively. Login to comment

[hide] The ABCR gene: a major disease gene in macular and... Mol Genet Metab. 1999 Oct;68(2):310-5. Rozet JM, Gerber S, Souied E, Ducroq D, Perrault I, Ghazi I, Soubrane G, Coscas G, Dufier JL, Munnich A, Kaplan J
The ABCR gene: a major disease gene in macular and peripheral retinal degenerations with onset from early childhood to the elderly.
Mol Genet Metab. 1999 Oct;68(2):310-5., [PMID:10527682]

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45 However, the G1961E, A1038V, G2588C alleles represent the most common mutant alleles in Europe and America (18.5, 18.5, and 6%, respectively) (8-11). Login to comment

[hide] Spectrum of ABCR gene mutations in autosomal reces... Eur J Hum Genet. 1998 May-Jun;6(3):291-5. Rozet JM, Gerber S, Souied E, Perrault I, Chatelin S, Ghazi I, Leowski C, Dufier JL, Munnich A, Kaplan J
Spectrum of ABCR gene mutations in autosomal recessive macular dystrophies.
Eur J Hum Genet. 1998 May-Jun;6(3):291-5., [PMID:9781034]

Abstract [show]
Stargardt disease (STGD) and late-onset fundus flavimaculatus (FFM) are autosomal recessive conditions leading to macular degenerations in childhood and adulthood, respectively. Recently, mutations of the photoreceptor cell-specific ATP binding transporter gene (ABCR) have been reported in Stargardt disease. Here, we report on the screening of the whole coding sequence of the ABCR gene in 40 unrelated STGD and 15 FFM families and we show that mutations truncating the ABCR protein consistently led to STGD. Conversely, all mutations identified in FFM were missense mutations affecting uncharged amino acids. These results provide the first genotype-phenotype correlations in ABCR gene mutations.

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43 By contrast, all mutations identified in FFM patients were missense mutations involving uncharged amino acids and none of them (except the A1038V mutation) were detected in STGD. Login to comment
44 Interestingly, the A1038V mutation was found in compound heterozygotes (one STGD, family CHE and one FFM, family VIL), the second mutation being another missense mutation in the FFM family (L541P) but a frameshift mutation in STGD (Table 1). Login to comment
45 Furthermore, all ABCR missense mutations Table 1 Mutations in the ABCR gene in STGD and FFM families Conserved aa in: Nucleotide change Amino acid change Domain ABCs RmP Phenotype Families Comment (571-2)A®G splicing mutation STGD 1 HAD1 (1938-2)A®G splicing mutation STGD 1 (4668+2)T®C splicing mutation STGD 1 (4735+2)T®A splicing mutation STGD 1 del(5196+1-5196+6 splicing mutation STGD 1 LOZ2 2570 delT frameshift mutation STGD 1 3209insGT frameshift mutation STGD 2 CHE2 G3754T E1252X STGD 1 C3994T Q1332X STGD 1 C6337G I2113X STGD 1 JEG2 C52T R18W IC - + STGD 1 C634T R212C EC - + STGD 5 GEN2, JEG2 G1908T Q636H IC - + STGD 1 LOZ2 C3056T T1019M IC - + STGD 1 C3322T R1107C IC - + STGD 1 JUL2 C4916T R1640W IC + + STGD 2 MAR1 G5929A G1977S ATP2 + + STGD 1 GEN2 G6320A R2107H IC + + STGD 1 JUL2 C3114T A1038V IC - + STGD 2 CHE2 +FFM +1 VII2 T1622C L541P EC - + FFM 1 VII2 T31C L11P IC + + FFM 1 G3272A G1090E IC + + FFM 1 G4522T G1508C IC + + FFM 1 C5908T L1970F IC + + FFM 1 GON2 T5912G L1971R IC + + FFM 1 GON2 Mutations refer to the standard nomenclature. Login to comment

[hide] ABC A-subfamily transporters: structure, function ... Biochim Biophys Acta. 2006 May;1762(5):510-24. Epub 2006 Feb 28. Kaminski WE, Piehler A, Wenzel JJ
ABC A-subfamily transporters: structure, function and disease.
Biochim Biophys Acta. 2006 May;1762(5):510-24. Epub 2006 Feb 28., [PMID:16540294]

Abstract [show]
ABC transporters constitute a family of evolutionarily highly conserved multispan proteins that mediate the translocation of defined substrates across membrane barriers. Evidence has accumulated during the past years to suggest that a subgroup of 12 structurally related "full-size" transporters, referred to as ABC A-subfamily transporters, mediates the transport of a variety of physiologic lipid compounds. The emerging importance of ABC A-transporters in human disease is reflected by the fact that as yet four members of this protein family (ABCA1, ABCA3, ABCR/ABCA4, ABCA12) have been causatively linked to completely unrelated groups of monogenetic disorders including familial high-density lipoprotein (HDL) deficiency, neonatal surfactant deficiency, degenerative retinopathies and congenital keratinization disorders. Although the biological function of the remaining 8 ABC A-transporters currently awaits clarification, they represent promising candidate genes for a presumably equally heterogenous group of Mendelian diseases associated with perturbed cellular lipid transport. This review summarizes our current knowledge on the role of ABC A-subfamily transporters in physiology and disease and explores clinical entities which may be potentially associated with dysfunctional members of this gene subfamily.

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178 Interestingly, some mutant alleles such as G863A, A1038V, and G1961E, respectively, appear to be more common and may have altered frequencies in different populations, presumably as a result of a founder effect [76,80]. Login to comment

[hide] Correlation between photoreceptor layer integrity ... Invest Ophthalmol Vis Sci. 2012 Jul 3;53(8):4409-15. doi: 10.1167/iovs.11-8201. Print 2012 Jul. Testa F, Rossi S, Sodi A, Passerini I, Di Iorio V, Della Corte M, Banfi S, Surace EM, Menchini U, Auricchio A, Simonelli F
Correlation between photoreceptor layer integrity and visual function in patients with Stargardt disease: implications for gene therapy.
Invest Ophthalmol Vis Sci. 2012 Jul 3;53(8):4409-15. doi: 10.1167/iovs.11-8201. Print 2012 Jul., [PMID:22661472]

Abstract [show]
PURPOSE: To perform a clinical characterization of Stargardt patients with ABCA4 gene mutation, and to investigate the correlation between the inner and outer segment (IS/OS) junction morphology and visual acuity, fundus lesions, electroretinogram abnormalities, and macular sensitivity. METHODS: Sixty-one patients with Stargardt disease (STGD) were given a comprehensive ophthalmic examination. Inner-outer photoreceptor junction morphology evaluated by spectral-domain optical coherence tomography was correlated with visual acuity, fundus lesions, fundus autofluorescence, full-field and multifocal electroretinography responses, and microperimetric macular sensitivities. We classified STGD patients into three groups: (1) IS/OS junction disorganization in the fovea, (2) IS/OS junction loss in the fovea, and (3) extensive loss of IS/OS junction. Mutation analysis of the ABCA4 gene was carried out by sequencing the complete coding region. RESULTS: A significant difference in visual acuity was observed between IS/OS groups 1 and 2 and between IS/OS groups 2 and 3 (P < 0.0001). A significant difference in microperimetry sensitivity was observed between IS/OS groups 2 and 3, and between IS/OS groups 1 and 3 (P < 0.0001). There was also a statistically significant correlation between IS/OS abnormalities and the extent of fundus lesions (Spearman P </= 0.01), as well as with the type of ERG and multifocal ERG results (Spearman P </= 0.01). Finally, the degree of IS/OS junction preservation showed a statistically significant correlation with the extension of foveal abnormalities assessed by fundus autofluorescence imaging (Spearman P </= 0.01). The G1961E mutation was more frequent in the patients without extensive loss of IS/OS junction (P = 0.01) confirming its association with a milder STGD phenotype. CONCLUSIONS: The results of this study suggest that a comprehensive approach in the examination of Stargardt patients has the potential to improve the understanding of vision loss and may provide a sensitive measure to evaluate the efficacy of future experimental therapies in patients with STGD.

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66 Clinical and Molecular Data of STGD Patients Patient ID/Fam Age (y) Visual Acuity OCT ft (lm) MP (dB) IS/OS* Fundus† FAF‡ ERG§ mfERGjj Mutation 1 Mutation 2 4/2 50 0.0715 134 5.25 - 1 - 2 4 G1961E 250InsCAAA 5/2 47 0.1 127 14.2 2 1 1 1 3 G1961E 250InsCAAA 6/3 33 0.05 125 9.8 2 2 2 1 3 G1961E R2149X 7/4 18 0.085 135 0 - 2 - 3 4 5917del G 5917del G 8/5 16 0.095 104 0.9 3 2 3 3 4 L541P; A1038V L541P; A1038V 9/6 71 0.03 109 0 3 3 3 2 4 IVS35þ2t > c G1961E 11/7 46 0.2 137 9.35 2 1 2 1 1 Y850K A1598D 13/8 35 0.017 163 0 - 3 - 3 4 L541P R1098C 15/10 20 0.1 135.5 11.05 2 1 1 1 4 IVS35þ2t > c G1961E 16/11 20 0.47 96 16.7 2 1 2 1 2 L541P; A1038V L541P; A1038V 17/11 34 0.1 114.5 7.55 2 1 2 1 3 L541P; A1038V L541P; A1038V 18/11 18 1 134 16.15 1 1 1 1 3 L541P; A1038V L541P; A1038V 19/12 12 0.12 242 6.5 3 1 2 1 2 L541P; A1038V L541P; A1038V 20/13 28 0.1 111 14.2 2 2 2 1 3 R1443H IVS35þ2t > c 21/14 34 0.2 152 14.15 2 1 2 2 4 R653C G1961E 22/15 69 0.079 122 0 3 3 3 3 4 I1562T R2149X 23/15 46 0.55 162 1.05 3 3 3 3 4 I1562T IVS45þ1g > c 25/16 28 0.11 105.5 3.1 3 2 2 3 4 R212C R212C 26/17 13 0.084 138.5 0.2 3 2 3 1 3 R18W C1490Y 27/4 20 0.0775 131 0 - 3 - 3 4 5917del G 5917del G 28/4 23 0.042 159.5 0 - 3 - 3 4 5917del G 5917del G 30/18 29 0.0375 103 0 3 3 3 3 4 N965S G1961E 31/19 17 0.1 102 9 3 2 2 3 4 L541P F655C 38/20 20 0.225 95 16 2 1 1 3 4 L541P G1961E 39/21 20 0.17 146 16.7 2 1 1 1 3 G1961E R2030X 42/22 43 0.575 127 7.05 2 1 2 1 2 250insCAAA G1961E 43/23 12 0.1 117.5 11.55 2 2 2 1 3 IVS40þ5g > a IVS15-8g > a 44/24 29 0.1 149 18.5 2 1 2 1 3 G1961E 4736del6bpins2bp 46/25 38 0.0075 182.5 0 - 3 - 3 4 G618R G1972R 48/26 35 0.46 133.5 12.25 2 1 - 1 3 4538insC G1961E 50/27 13 0.2 122.5 17.35 2 1 2 1 3 IVS35þ2t > c G1961E 51/28 24 0.065 123 0 3 3 3 3 4 250InsCAAA V767D 52/29 14 1 147 6.15 1 1 1 3 4 L2027F A1881V 53/30 45 0.1 120 6.05 3 2 2 1 3 G1961E R2030X 54/30 24 0.09 159 2.65 3 3 3 3 4 V767D R2030X 55/31 34 0.085 150 5.15 3 3 3 3 4 N96H IVS40þ5g > a 56/32 48 0.0335 118.5 4.4 - 3 - 2 4 IVS35þ2t > c G1961E 58/32 52 0.05 124 5.8 3 2 2 2 4 IVS35þ2t > c G1961E 60/33 43 0.065 163 15.95 2 1 - 1 2 250InsCAAA G1961E 61/34 45 0.03 187.5 4.5 1 1 1 2 1 R1640Q G1961E 64/35 33 0.0665 158 0 3 3 3 3 4 C2150R 2626InsTTT 65/35 38 0.008 172 0.05 3 3 3 3 4 C2150R 2626InsTTT 66/36 42 0.4 137 0.95 3 2 2 1 3 N96D IVS40þ5g > a 67/37 14 0.235 132 0.15 3 2 3 3 4 IVS6-2a > t IVS6-2a > t 69/38 19 0.09 120 0 3 1 2 1 3 R511H N529S 70/39 42 0.515 140 0.4 3 3 3 3 4 IVS40þ5g > a N965S 72/40 33 0.096 116.5 5.1 3 2 2 1 3 N96D L2140Q 73/41 17 0.1 160 14.35 2 2 2 3 4 G690D A1598D 74/42 36 0.0125 142.5 0 3 3 3 3 4 N96H N96H 75/43 45 0.2 214.5 11.7 2 1 2 1 3 IVS35þ2t > c G1961E 77/44 19 0.34 137.5 11.75 2 1 - 1 3 G1961E G618R 81/45 66 0.335 163 2 - 3 - 2 4 N96D G1961E 82/46 41 0.1 116.5 0.15 3 3 3 3 4 4538insC IVS40þ5g > a 83/47 17 0.395 165 19.25 1 1 1 1 2 G1961E IVS45þ1g > c 84/47 26 0.135 120 16.2 2 1 2 1 3 G1961E IVS45þ1g > c 85/48 10 0.16 149.5 12.4 2 2 2 1 3 IVS35þ2t > c IVS40þ5g > a 87/40 25 0.9 155 15 2 1 2 1 2 N96D L2140Q 88/49 32 0.0715 144 0.1 - 3 - 3 4 IVS45þ1g > c R2149X 89/50 14 0.1185 147 1.85 3 1 - 3 4 P402A 250insCAAA 90/51 35 0.07 116.5 0 - 3 - 3 4 A1598D R2030X 94/52 30 0.1 144 12.85 2 1 - 1 1 A1598D G1961E Fam, family; OCT ft, optical coherence tomography foveal thickness; MP, microperimetry; IS/OS, inner-outer segment junction; FAF, fundus autofluorescence; ERG, electroretinogram; mfERG, multifocal-electroretinogram. Login to comment
67 Clinical and Molecular Data of STGD Patients Patient ID/Fam Age (y) Visual Acuity OCT ft (lm) MP (dB) IS/OS* Fundusߤ FAFߥ ERG&#a7; mfERGjj Mutation 1 Mutation 2 4/2 50 0.0715 134 5.25 - 1 - 2 4 G1961E 250InsCAAA 5/2 47 0.1 127 14.2 2 1 1 1 3 G1961E 250InsCAAA 6/3 33 0.05 125 9.8 2 2 2 1 3 G1961E R2149X 7/4 18 0.085 135 0 - 2 - 3 4 5917del G 5917del G 8/5 16 0.095 104 0.9 3 2 3 3 4 L541P; A1038V L541P; A1038V 9/6 71 0.03 109 0 3 3 3 2 4 IVS35&#fe;2t > c G1961E 11/7 46 0.2 137 9.35 2 1 2 1 1 Y850K A1598D 13/8 35 0.017 163 0 - 3 - 3 4 L541P R1098C 15/10 20 0.1 135.5 11.05 2 1 1 1 4 IVS35&#fe;2t > c G1961E 16/11 20 0.47 96 16.7 2 1 2 1 2 L541P; A1038V L541P; A1038V 17/11 34 0.1 114.5 7.55 2 1 2 1 3 L541P; A1038V L541P; A1038V 18/11 18 1 134 16.15 1 1 1 1 3 L541P; A1038V L541P; A1038V 19/12 12 0.12 242 6.5 3 1 2 1 2 L541P; A1038V L541P; A1038V 20/13 28 0.1 111 14.2 2 2 2 1 3 R1443H IVS35&#fe;2t > c 21/14 34 0.2 152 14.15 2 1 2 2 4 R653C G1961E 22/15 69 0.079 122 0 3 3 3 3 4 I1562T R2149X 23/15 46 0.55 162 1.05 3 3 3 3 4 I1562T IVS45&#fe;1g > c 25/16 28 0.11 105.5 3.1 3 2 2 3 4 R212C R212C 26/17 13 0.084 138.5 0.2 3 2 3 1 3 R18W C1490Y 27/4 20 0.0775 131 0 - 3 - 3 4 5917del G 5917del G 28/4 23 0.042 159.5 0 - 3 - 3 4 5917del G 5917del G 30/18 29 0.0375 103 0 3 3 3 3 4 N965S G1961E 31/19 17 0.1 102 9 3 2 2 3 4 L541P F655C 38/20 20 0.225 95 16 2 1 1 3 4 L541P G1961E 39/21 20 0.17 146 16.7 2 1 1 1 3 G1961E R2030X 42/22 43 0.575 127 7.05 2 1 2 1 2 250insCAAA G1961E 43/23 12 0.1 117.5 11.55 2 2 2 1 3 IVS40&#fe;5g > a IVS15-8g > a 44/24 29 0.1 149 18.5 2 1 2 1 3 G1961E 4736del6bpins2bp 46/25 38 0.0075 182.5 0 - 3 - 3 4 G618R G1972R 48/26 35 0.46 133.5 12.25 2 1 - 1 3 4538insC G1961E 50/27 13 0.2 122.5 17.35 2 1 2 1 3 IVS35&#fe;2t > c G1961E 51/28 24 0.065 123 0 3 3 3 3 4 250InsCAAA V767D 52/29 14 1 147 6.15 1 1 1 3 4 L2027F A1881V 53/30 45 0.1 120 6.05 3 2 2 1 3 G1961E R2030X 54/30 24 0.09 159 2.65 3 3 3 3 4 V767D R2030X 55/31 34 0.085 150 5.15 3 3 3 3 4 N96H IVS40&#fe;5g > a 56/32 48 0.0335 118.5 4.4 - 3 - 2 4 IVS35&#fe;2t > c G1961E 58/32 52 0.05 124 5.8 3 2 2 2 4 IVS35&#fe;2t > c G1961E 60/33 43 0.065 163 15.95 2 1 - 1 2 250InsCAAA G1961E 61/34 45 0.03 187.5 4.5 1 1 1 2 1 R1640Q G1961E 64/35 33 0.0665 158 0 3 3 3 3 4 C2150R 2626InsTTT 65/35 38 0.008 172 0.05 3 3 3 3 4 C2150R 2626InsTTT 66/36 42 0.4 137 0.95 3 2 2 1 3 N96D IVS40&#fe;5g > a 67/37 14 0.235 132 0.15 3 2 3 3 4 IVS6-2a > t IVS6-2a > t 69/38 19 0.09 120 0 3 1 2 1 3 R511H N529S 70/39 42 0.515 140 0.4 3 3 3 3 4 IVS40&#fe;5g > a N965S 72/40 33 0.096 116.5 5.1 3 2 2 1 3 N96D L2140Q 73/41 17 0.1 160 14.35 2 2 2 3 4 G690D A1598D 74/42 36 0.0125 142.5 0 3 3 3 3 4 N96H N96H 75/43 45 0.2 214.5 11.7 2 1 2 1 3 IVS35&#fe;2t > c G1961E 77/44 19 0.34 137.5 11.75 2 1 - 1 3 G1961E G618R 81/45 66 0.335 163 2 - 3 - 2 4 N96D G1961E 82/46 41 0.1 116.5 0.15 3 3 3 3 4 4538insC IVS40&#fe;5g > a 83/47 17 0.395 165 19.25 1 1 1 1 2 G1961E IVS45&#fe;1g > c 84/47 26 0.135 120 16.2 2 1 2 1 3 G1961E IVS45&#fe;1g > c 85/48 10 0.16 149.5 12.4 2 2 2 1 3 IVS35&#fe;2t > c IVS40&#fe;5g > a 87/40 25 0.9 155 15 2 1 2 1 2 N96D L2140Q 88/49 32 0.0715 144 0.1 - 3 - 3 4 IVS45&#fe;1g > c R2149X 89/50 14 0.1185 147 1.85 3 1 - 3 4 P402A 250insCAAA 90/51 35 0.07 116.5 0 - 3 - 3 4 A1598D R2030X 94/52 30 0.1 144 12.85 2 1 - 1 1 A1598D G1961E Fam, family; OCT ft, optical coherence tomography foveal thickness; MP, microperimetry; IS/OS, inner-outer segment junction; FAF, fundus autofluorescence; ERG, electroretinogram; mfERG, multifocal-electroretinogram. Statistics Our set of data is described by continuous (BCVA, OCT foveal thickness, and macular sensitivities) and categorical (fundus, FAF, IS/ OS, ERG, and mfERG groups) variables. Login to comment

[hide] Foveal cavitation as an optical coherence tomograp... Retina. 2012 Jul;32(7):1411-9. Leng T, Marmor MF, Kellner U, Thompson DA, Renner AB, Moore W, Sowden JC
Foveal cavitation as an optical coherence tomography finding in central cone dysfunction.
Retina. 2012 Jul;32(7):1411-9., [PMID:22466470]

Abstract [show]
PURPOSE: To describe a distinctive foveal cavitation as seen by spectral-domain optical coherence tomography in certain cone dysfunction syndromes. METHODS: Observational case series. Patients were evaluated by dilated fundus examination, fundus photography, fundus autofluorescence, full-field electroretinogram, multifocal electroretinogram, spectral-domain optical coherence tomography, color vision testing, fluorescein angiography, Goldmann visual field testing, and molecular genetic analysis. RESULTS: We present eight patients with foveal cavitation in association with presumed cone dysfunction. This was characterized on spectral-domain optical coherence tomography by a gap in the subfoveal outer segment layer without more diffuse retinal thinning. There were 5 patients of age 10 years to 27 years and 3 patients of age 49 years to 52 years, with a 1.5- to 38-year history of bilateral visual loss. A small foveal oval-shaped area of reduced foveal fundus autofluorescence, surrounded by increased fundus autofluorescence, was seen in the younger patients, and a broad circle of increased fundus autofluorescence in the older patients. The multifocal electroretinogram always showed central amplitude reduction, but there were varying degrees of cone dysfunction on full-field electroretinogram. There were mild abnormalities on desaturated color vision testing. The family history was noncontributory in all cases. None of the cases were congenital. ABCA4 gene mutations were identified in three of five patients tested; CNGB3 testing was negative in these patients. CONCLUSION: Cone dysfunction syndromes typically show retinal thinning on optical coherence tomography imaging, although several case reports have noted focal outer retinal loss. Our case series shows that a distinctive optical coherence tomography finding, foveal cavitation, may be a clue to cone dysfunction syndromes, but is not specific to any one hereditary disorder or age group.

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88 Previous reports by Cella et al10 and by Gomes et al11 describe cases of ABCA4 mutations involving L541P/ A1038V and G1961E. Login to comment
90 Cella et al10 proposed that the G1961E allele in either homozygosity or heterozygosity is associated with anatomical and functional pathologies limited to the parafoveal region; however, this mutation was present as a heterozygous mutation in only 2 of 5 cases tested (Cases 4 and 5) and L541P/A1038V was not present. Login to comment

[hide] A subgroup of age-related macular degeneration is ... Invest Ophthalmol Vis Sci. 2012 Apr 30;53(4):2112-8. doi: 10.1167/iovs.11-8785. Print 2012 Apr. Fritsche LG, Fleckenstein M, Fiebig BS, Schmitz-Valckenberg S, Bindewald-Wittich A, Keilhauer CN, Renner AB, Mackensen F, Mossner A, Pauleikhoff D, Adrion C, Mansmann U, Scholl HP, Holz FG, Weber BH
A subgroup of age-related macular degeneration is associated with mono-allelic sequence variants in the ABCA4 gene.
Invest Ophthalmol Vis Sci. 2012 Apr 30;53(4):2112-8. doi: 10.1167/iovs.11-8785. Print 2012 Apr., [PMID:22427542]

Abstract [show]
Purpose. Age-related macular degeneration (AMD) is a heterogeneous condition of high prevalence and complex etiology involving genetic as well as environmental factors. By fundus autofluorescence (FAF) imaging, AMD can be classified into several distinct phenotypes, with one subgroup characterized by fine granular pattern with peripheral punctate spots (GPS[+]). Some features of GPS[+] overlap with Stargardt disease (STGD1), a recessive macular dystrophy caused by biallelic sequence variants in the ATP-binding cassette transporter 4 (ABCA4) gene. The aim of this study was to investigate the role of ABCA4 in GPS[+]. Methods. The ABCA4 gene was sequenced in 25 patients with the GPS[+] phenotype and 29 with geographic atrophy (GA)-AMD but no signs of GPS (GPS[-]). In addition, frequencies of risk-increasing alleles at three known AMD susceptibility loci, including complement factor H (CFH), age-related maculopathy susceptibility 2 (ARMS2), and complement component 3 (C3), were evaluated. Results. We demonstrate that GPS[+] is associated significantly with monoallelic ABCA4 sequence variants. Moreover, frequencies of AMD risk-increasing alleles at CFH, ARMS2, and C3 are similar in GPS[+] and STGD1 patients, with risk allele frequencies in both subcategories comparable to population-based control individuals estimated from 3,510 individuals from the NHLBI Exome Sequencing Project. Conclusions. Our data suggest that the GPS[+] phenotype is accounted for by monoallelic variants in ABCA4 and unlikely by the well-established AMD risk-increasing alleles at CFH, ARMS2, and C3. These findings provide support for a complex role of ABCA4 in the etiology of a minor proportion of patients with AMD.

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71 The heterozygous change c.3113C>T (p.A1038V) was found in five patients together with c.1622T>C (p.L541P) and in another two patients together with c.3261A>C (p.E1087D, patient L-099-GA) and c.3752delA (p.E1251fs, patient H-144-GA), respectively. Login to comment
88 The patient carries a heterozygous, complex disease allele (c.1622T>C, p.L541P; c.3113C>T, p.A1038V) in the ABCA4 gene. Login to comment
89 directly the cis configuration of the c.3113C>T / c.1622T>C alleles in one case by segregation analysis (patient M07-0338- 11,085), these two variants have been shown repeatedly in previous studies to occur as a frequent complex allele on a single chromosome.10,36 Trans-configuration was confirmed for heterozygous changes c.3113C>T (p.A1038V) / c.3261A>C (p.E1087D) in patient L-099-GA. Login to comment
90 Due to lack of DNA from further family members, segregation of variants c.3113C>T (p.A1038V) / c.3752delA (p.Glu1251fs) and c.1804C>T (p.R602W) / c.1928T>G (p.V643G) could not be assessed further (Supplementary Table S5). Login to comment
120 In this context, it may be of interest that the complex allele L541P/ A1038V was found in 5/20 GPS[+] alleles. Login to comment
121 If one further includes the single A1038V variant, which was found twice in GPS[+], there is a striking overabundance of A1038V alleles in GPS[+] (35% of all alleles identified). Login to comment
122 Although the GPS[+] patient group is small in number and, therefore, prone to random findings, our data may still point to the possibility that only a certain type of variant, such as A1038V, could be associated with the GPS[+] phenotype. Login to comment
69 The heterozygous change c.3113C>T (p.A1038V) was found in five patients together with c.1622T>C (p.L541P) and in another two patients together with c.3261A>C (p.E1087D, patient L-099-GA) and c.3752delA (p.E1251fs, patient H-144-GA), respectively. Login to comment
86 The patient carries a heterozygous, complex disease allele (c.1622T>C, p.L541P; c.3113C>T, p.A1038V) in the ABCA4 gene. Login to comment
87 directly the cis configuration of the c.3113C>T / c.1622T>C alleles in one case by segregation analysis (patient M07-0338- 11,085), these two variants have been shown repeatedly in previous studies to occur as a frequent complex allele on a single chromosome.10,36 Trans-configuration was confirmed for heterozygous changes c.3113C>T (p.A1038V) / c.3261A>C (p.E1087D) in patient L-099-GA. Login to comment
118 In this context, it may be of interest that the complex allele L541P/ A1038V was found in 5/20 GPS[+] alleles. Login to comment
119 If one further includes the single A1038V variant, which was found twice in GPS[+], there is a striking overabundance of A1038V alleles in GPS[+] (35% of all alleles identified). Login to comment

[hide] Macular function in macular degenerations: repeata... Invest Ophthalmol Vis Sci. 2012 Feb 21;53(2):841-52. Print 2012 Feb. Cideciyan AV, Swider M, Aleman TS, Feuer WJ, Schwartz SB, Russell RC, Steinberg JD, Stone EM, Jacobson SG
Macular function in macular degenerations: repeatability of microperimetry as a potential outcome measure for ABCA4-associated retinopathy trials.
Invest Ophthalmol Vis Sci. 2012 Feb 21;53(2):841-52. Print 2012 Feb., [PMID:22247458]

Abstract [show]
PURPOSE: To measure macular visual function in patients with unstable fixation, to define the photoreceptor source of this function, and to estimate its test-retest repeatability as a prerequisite to clinical trials. METHODS: Patients (n = 38) with ABCA4-associated retinal degeneration (RD) or with retinitis pigmentosa (RP) were studied with retina-tracking microperimetry along the foveo-papillary profile between the fovea and the optic nerve head, and point-by-point test-retest repeatability was estimated. A subset with foveal fixation was also studied with dark-adapted projection perimetry using monochromatic blue and red stimuli along the horizontal meridian. RESULTS: Macular function in ABCA4-RD patients transitioned from lower sensitivity at the parafovea to higher sensitivity in the perifovea. RP patients had the inverse pattern. Red-on-red microperimetric sensitivities successfully avoided ceiling effects and were highly correlated with absolute sensitivities. Point-by-point test-retest limits (95% confidence intervals) were +/-4.2 dB; repeatability was not related to mean sensitivity, eccentricity from the fovea, age, fixation location, or instability. Repeatability was also not related to the local slope of sensitivity and was unchanged in the parapapillary retina. CONCLUSIONS: Microperimetry allows reliable testing of macular function in RD patients without foveal fixation in longitudinal studies evaluating natural disease progression or efficacy of therapeutic trials. A single estimate of test-retest repeatability can be used to determine significant changes in visual function at individual retinal loci within diseased regions that are homogeneous and those that are heterogeneous and also in transition zones at high risk for disease progression.

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42 Clinical and Molecular Characteristics of the ABCA4 Patients Patient Age (y)/Sex ABCA4 Mutation Clinical Diagnosis Visual Acuity* Kinetic Visual Field Extent (V-4e)†Allele 1 Allele 2 Foveal Fixation P1‡ 12/M N965S W821R STGD 20/20 97 P2‡ 17/F V989A IVS28ϩ5 GϾT STGD 20/100 90 P3 18/M G1961E R1129L§ STGD 20/100 105 P4 21/F R212C P68R STGD 20/125 101 P5 24/M P1511 del1ccgC R1705Q STGD 20/25 114 P6 31/M G863A R1108C STGD 20/25 105 P7 32/F IVS40ϩ5 GϾA V935A STGD 20/32 103 P8 34/M G1961E - CRD 20/32 98 P9 37/F R681X P309R STGD 20/20 109 P10 39/M G1961E C54Y§ STGD 20/40 101 P11‡ 42/F G1961E V256V STGD 20/32 105 P12‡ 46/F G1961E V256V STGD 20/32 106 P13 52/F G1961E P1380L STGD 20/40 105 P14 58/M D600E R18W§ STGD 20/40 84 Extrafoveal Fixation P15 11/M V256V T1526M CRD 20/200 102 P16 15/M C54Y IVS35ϩ2 TϾC STGD 20/200 96 P17‡ 16/F V989A IVS28ϩ5 GϾT STGD 20/100 100 P18‡ 16/M N965S W821R STGD 20/125 100 P19 19/F A1038V/L541P N965S STGD 20/400 90 P20 21/M G863A IVS35ϩ2 TϾC STGD 20/200 99 P21 22/F G1961E R152X STGD 20/50 104 P22 27/M G863A P1660S§ STGD 20/100 98 P23 27/F G1961E A1038V/L541P STGD 20/100 109 P24 29/M G1961E T1019M STGD 20/100 104 P25 33/M P1486L deletion of exon 7 STGD 20/400 98 P26 36/F G863A C1490Y STGD 20/100 93 P27 41/M A1038V/L541P - STGD 20/125 108 P28 49/F T1526M R2030Q STGD 20/125 98 P29 55/F W855X - STGD 20/160 87 P30 56/F G1961E IVS37ϩ1 GϾA§ STGD 20/125 89 P31 60/F G1961E M669 del2ccAT STGD 20/125 104 STGD, Stargardt disease; CRD, cone-rod dystrophy. Login to comment

[hide] Phenotypic and genetic spectrum of Danish patients... Ophthalmic Genet. 2012 Dec;33(4):225-31. doi: 10.3109/13816810.2011.643441. Epub 2012 Jan 9. Duno M, Schwartz M, Larsen PL, Rosenberg T
Phenotypic and genetic spectrum of Danish patients with ABCA4-related retinopathy.
Ophthalmic Genet. 2012 Dec;33(4):225-31. doi: 10.3109/13816810.2011.643441. Epub 2012 Jan 9., [PMID:22229821]

Abstract [show]
Background: Pathogenic variations in the ABCA4 gene were originally recognized as genetic background for the autosomal recessive disorders Stargardt disease and fundus flavimaculatus, but have expanded to embrace a diversity of retinal diseases, giving rise to the new diagnostic term, ABCA4-related retinopathy. Diagnostic genotyping of ABCA4 is complicated by the large size of the gene and the existence of approximately 600 known pathogenic variations, along with numerous rare polymorphisms. A commercial diagnostic array-based assay has been developed targeting known mutations, however a conclusive genetic diagnosis must rely on a comprehensive genetic screening as the mutation spectrum of ABCA4-related retinopathies continues to expand. Material and methods: Among 161 patients with a Stargardt-related phenotype previously assessed with the commercial ABCA4 mutation microarray, we analyzed the ABCA4 gene with High-resolution melting (HRM) in patients in whom the array analysis identified either a heterozygous mutation (n = 50) or no mutation (n = 30). Results: The HRM method detected each of the already known mutations and polymorphisms. We identified the second ABCA4 mutation in 31 of 50 heterozygous patients (62%). Several novel mutations were identified of which four were identified multiple times. The recurrent novel mutations were subsequently assessed among the 30 patients with possible ABCA4-related diseases, previously found to be negative for known ABCA4 mutations by array analysis. In total, 30 different mutations were identified of which 21 have not been described before. Conclusion: Scandinavian patients with ABCA4-related retinopathy appear to have a distinct mutation spectrum, which can be identified in patients of diverse clinical phenotypes.

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56 Table 1 Mutations identified by HRM in the initial 50 heterozygous patients Patient Mutation 1 (Asper) Mutation 2 (HRM) RefDNA Protein Exon/intron DNA Protein Exon/intron D043 c.2588G>C p.G863A 17 c.184 C>T p.P62S 3 New D069 c.3113C>T p.A1038V 21 c.1529 T>G p.L510R 11 New D050 c.2588G>C p.G863A 17 c.1529 T>G p.L510R 11 New D112 c.2894A>G p.N965S 19 c.1529 T>G p.L510R 11 New D099 c.6089G>A p.R2030Q 44 c.1529 T>G p.L510R 11 New D165 c.1822T>C p.F608L 13 c.2243 G>A p.C748Y 15 New D166 c.2588G>C p.G863A 17 c.2300 T>A p.V767D 15 Known D117 c.3191-2A>G na IVS21 c.2408delG na 16 New D135 c.2894A>G p.N965S 19 c.2408delG na 16 New D147 c.2894A>G p.N965S 19 c.2408delG na 16 New D173 c.4469G>A p.C1490Y 30 c.2915C>A p.T972N 19 Known D013* c.1622C>T p.L541P 12 c.1313C>T p.A1038V 21 Known D181 c.6089G>A p.R2030Q 44 c.3380 G>A p.G1127E 23 New D018 c.6449G>A p.C2150Y 47 c.3736 C>G p.L1246V 25 New D191 c.2588G>C p.G863A 17 c.4069 G>A p.A1357T 27 New D167 c.5461-10T>C na IVS38 c.4102 C>T p.R1368C 27 New D022 c.4462T>C p.C1488R 30 c.4102 C>T p.R1368C 27 New D108 c.1648G>A p.G550R 12 c.4102 C>T p.R1368C 27 New D414 c.2588G>C p.G863A 17 c.4653 G>A p.W1551X 32 New D027 c.2588G>C p.G863A 17 c.4668-2A>G na IVS32 New D136 c. Login to comment
57 [1622C>T+3113C>T] p.[L541P+A1038V] 12 c.4739T>C p.L1580S 33 Known D444 c.2701A>G p.T901A 18 c.4773 + 3A>G na IVS33 New D034 c.2588G>C p.G863A 17 c.4773 + 5G>A na IVS33 New D178 c.3113C>T p.A1038V 21 c.5523_5528del p.1843_1844delRG 39 New D110 c. Login to comment
58 [1622C>T+3113C>T] p.[L541P+A1038V] 12 c.5584 + 1G>A na IVS39 New D188 c.5461-10T>C na IVS38 c.5693G>A p.R1898H 40 Known D433 c.5882G>A p.G1961E 42 c.6005 + 1G>A na IVS43 Known D134 c.4667 + 2G>T na IVS32 c.6098 T>G p.L2033R 44 New D186 c.3322C>T p.R1108C 22 c.6386 + 1G>A na IVS46 New D182 c.6089G>A p.R2030Q 44 c.6386 + 1G>A na IVS46 New D189 c.2894A>G p.N965S 19 c.6478 A>G p.K2160E 47 New *p.L541P and p.A1038V might be located on the same allele. Login to comment
97 Phenotype Patient Mutation 1 Mutation 2 Mutation 3 Stargardt-flavimaculatus D043 p.G863A p.P62S D050 p.G863A p.L510R D112 p.N965S p.L510R D069 p.A1038V p.L510R D099 p.R2030Q p.L510R D178 p.A1038V c.1843_1844delRG D166 p.G863A p.V767D D191 p.G863A p.A1357T D167 c.5461-10T>C p.R1368C D128 p.2408delG* p.T1415P D027 p.G863A c.4668-2A>G* D136 p.[L541P+A1038V] p.L1580S D048 c.3766dupTG* p.R1898H p.F655C D034 p.G863A c.4773 + 5G>A* D015 p. G1127K p.K2160E p.V552I D189 p.N965S p.K2160E D433 p.G1961E c.6005 + 1G>A* Generalized retinal dystrophy D117 c.3191-2A>G* c.2408delG* D135 p.N965S c.2408delG* D147 p.N965S c.2408delG* D173 p.C1490Y p.T972N D018 p.C2150Y p.L1246V D022 p.C1488R p.R1368C D108 p.G550R p.R1368C D414 p.G863A p.W1551X* D444 p.T901A c.4773 + 3A>G* D110 p.[L541P+A1038V] c.5584 + 1G>A* D182 p.R2030Q c.6386 + 1G>A* D186 p.R1108C c.6386 + 1G>AA* D133 p.L510R IVS46 + 1G>A* Cone-rod dystrophy D134 c.4667 + 2G>T* p.L2033R Atypical maculopathy D165 p.F608L p.C748Y D181 p.R2030Q p.G1127E D188 c.5461-10T>C p.R1898H *Predicted to compromise correct reading frame. Login to comment
101 We have previously shown that the mutation spectrum of recessive diseases in the Danish population can be quite different from populations in central Europe.21,22 A similar diverse ABCA4 mutation spectrum has been described for other European populations.14,16 Patient D013 was by array analysis solely found to be heterozygous for the common p.P541L mutation, which usually is allelic to p.A1038V. Login to comment
102 In fact p.[P541L+A1038V] was the third most common allele in our initial array analysis and is one of the most prevalent European mutations.23 HRM identified p.A1038V as the second mutation in D013, thus this mutation was missed by array analysis, and the patient is most likely "only" a carrier for the p.[P541L+A1038V]. Login to comment
105 In sample D015 the known p.V552I mutation was identified along with the newly identified p.K2160E and p.G1127E variations. Login to comment
120 The remaining two patients were heterozygous for the known p.A1038V and p.R1098C mutations, respectively. Login to comment
59 [1622C>T+3113C>T] p.[L541P+A1038V] 12 c.4739T>C p.L1580S 33 Known D444 c.2701A>G p.T901A 18 c.4773ߙ+ߙ3A>G na IVS33 New D034 c.2588G>C p.G863A 17 c.4773ߙ+ߙ5G>A na IVS33 New D178 c.3113C>T p.A1038V 21 c.5523_5528del p.1843_1844delRG 39 New D110 c. Login to comment
60 [1622C>T+3113C>T] p.[L541P+A1038V] 12 c.5584ߙ+ߙ1G>A na IVS39 New D188 c.5461-10T>C na IVS38 c.5693G>A p.R1898H 40 Known D433 c.5882G>A p.G1961E 42 c.6005ߙ+ߙ1G>A na IVS43 Known D134 c.4667ߙ+ߙ2G>T na IVS32 c.6098 T>G p.L2033R 44 New D186 c.3322C>T p.R1108C 22 c.6386ߙ+ߙ1G>A na IVS46 New D182 c.6089G>A p.R2030Q 44 c.6386ߙ+ߙ1G>A na IVS46 New D189 c.2894A>G p.N965S 19 c.6478 A>G p.K2160E 47 New *p.L541P and p.A1038V might be located on the same allele. Login to comment
100 Phenotype Patient Mutation 1 Mutation 2 Mutation 3 Stargardt-flavimaculatus D043 p.G863A p.P62S D050 p.G863A p.L510R D112 p.N965S p.L510R D069 p.A1038V p.L510R D099 p.R2030Q p.L510R D178 p.A1038V c.1843_1844delRG D166 p.G863A p.V767D D191 p.G863A p.A1357T D167 c.5461-10T>C p.R1368C D128 p.2408delG* p.T1415P D027 p.G863A c.4668-2A>G* D136 p.[L541P+A1038V] p.L1580S D048 c.3766dupTG* p.R1898H p.F655C D034 p.G863A c.4773ߙ+ߙ5G>A* D015 p. G1127K p.K2160E p.V552I D189 p.N965S p.K2160E D433 p.G1961E c.6005ߙ+ߙ1G>A* Generalized retinal dystrophy D117 c.3191-2A>G* c.2408delG* D135 p.N965S c.2408delG* D147 p.N965S c.2408delG* D173 p.C1490Y p.T972N D018 p.C2150Y p.L1246V D022 p.C1488R p.R1368C D108 p.G550R p.R1368C D414 p.G863A p.W1551X* D444 p.T901A c.4773ߙ+ߙ3A>G* D110 p.[L541P+A1038V] c.5584ߙ+ߙ1G>A* D182 p.R2030Q c.6386ߙ+ߙ1G>A* D186 p.R1108C c.6386ߙ+ߙ1G>AA* D133 p.L510R IVS46ߙ+ߙ1G>A* Cone-rod dystrophy D134 c.4667ߙ+ߙ2G>T* p.L2033R Atypical maculopathy D165 p.F608L p.C748Y D181 p.R2030Q p.G1127E D188 c.5461-10T>C p.R1898H *Predicted to compromise correct reading frame. Login to comment
104 We have previously shown that the mutation spectrum of recessive diseases in the Danish population can be quite different from populations in central Europe.21,22 A similar diverse ABCA4 mutation spectrum has been described for other European populations.14,16 Patient D013 was by array analysis solely found to be heterozygous for the common p.P541L mutation, which usually is allelic to p.A1038V. Login to comment
123 The remaining two patients were heterozygous for the known p.A1038V and p.R1098C mutations, respectively. Login to comment

[hide] Stargardt macular dystrophy: common ABCA4 mutation... Mol Vis. 2012;18:280-9. Epub 2012 Feb 1. Roberts LJ, Nossek CA, Greenberg LJ, Ramesar RS
Stargardt macular dystrophy: common ABCA4 mutations in South Africa--establishment of a rapid genetic test and relating risk to patients.
Mol Vis. 2012;18:280-9. Epub 2012 Feb 1., [PMID:22328824]

Abstract [show]
PURPOSE: Based on the previous indications of founder ATP-binding cassette sub-family A member 4 gene (ABCA4) mutations in a South African subpopulation, the purpose was to devise a mechanism for identifying common disease-causing mutations in subjects with ABCA4-associated retinopathies (AARs). Facilitating patient access to this data and determining the frequencies of the mutations in the South African population would enhance the current molecular diagnostic service offered. METHODS: The majority of subjects in this study were of Caucasian ancestry and affected with Stargardt macular dystrophy. The initial cohort consisted of DNA samples from 181 patients, and was screened using the ABCR400 chip. An assay was then designed to screen a secondary cohort of 72 patients for seven of the most commonly occurring ABCA4 mutations in this population. A total of 269 control individuals were also screened for the seven ABCA4 mutations. RESULTS: Microarray screening results from a cohort of 181 patients affected with AARs revealed that seven ABCA4 mutations (p.Arg152*, c.768G>T, p.Arg602Trp, p.Gly863Ala, p.Cys1490Tyr, c.5461-10T>C, and p.Leu2027Phe) occurred at a relatively high frequency. The newly designed genetic assay identified two of the seven disease-associated mutations in 28/72 patients in a secondary patient cohort. In the control cohort, 12/269 individuals were found to be heterozygotes, resulting in an estimated background frequency of these mutations in this particular population of 4.46 per 100 individuals. CONCLUSIONS: The relatively high detection rate of seven ABCA4 mutations in the primary patient cohort led to the design and subsequent utility of a multiplex assay. This assay can be used as a viable screening tool and to reduce costs and laboratory time. The estimated background frequency of the seven ABCA4 mutations, together with the improved diagnostic service, could be used by counselors to facilitate clinical and genetic management of South African families with AARs.

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139 of alleles detected Frequency p.Cys54Tyr c. 161 G>A 2 0.55% p.Arg152* c. 454 C>T 12 3.31% p.Arg152Gln c. 455 G>A 3 0.83% p.Gly172Ser c. 514 G>A 1 0.28% p.Arg212Cys c. 634 C>T 1 0.28% p.Lys223Gln c. 667 A>C 1 0.28% p.V256V (Splice) c. 768 G>T 18 4.97% p.Pro291Leu c. 872 C>T 1 0.28% p.Trp439* c. 1317 G>A 1 0.28% p.Ala538Asp c. 1613 C>A 1 0.28% p.Leu541Pro c. 1622 T>C 1 0.28% p.Arg602Trp c. 1885C>T 30 8.29% p.Val643Met c. 1927 G>A 1 0.28% p.Arg653Cys c. 1957 C>T 1 0.28% p.Arg681* c. 2041 C>T 3 0.83% p.Val767Asp c. 2300 T>A 1 0.28% p.Trp855* c.2564_2571delGGTACCTT 2 0.55% p.Gly863Ala c. 2588 G>C 11 3.04% p.Val931Met c. 2791 G>A 1 0.28% p.Asn965Ser c. 2894 A>G 4 1.10% p.Val989Ala c. 2966 T>C 1 0.28% p.Gly991Arg c. 2971 G>C 1 0.28% p.Thr1019Met c. 3056 C>T 1 0.28% p.Ala1038Val c. 3113 C>T 3 0.83% p.Glu1087Lys c. 3259 G>A 1 0.28% p.Arg1108Cys c. 3322 C>T 2 0.55% p.Leu1201Arg c. 3602 T>G 4 1.10% p.Arg1300Gln c. 3899 G>A 4 1.10% p.Pro1380Leu c. 4139 C>T 3 0.83% p.Trp1408Arg c. 4222 T>C 1 0.28% - c. 4253+5G>A 1 0.28% p.Phe1440Ser c. 4319 T>C 1 0.28% p.Arg1443His c. 4328 G>A 1 0.28% p.Cys1490Tyr c.4469 G>A 54 14.92% p.Gln1513Pro fs*42 c. 4535 insC 1 0.28% p.Ala1598Asp c. 4793C>A 1 0.28% p.Arg1640Trp c. 4918 C>T 2 0.55% p.Ser1642Arg c. 4926 C>G 1 0.28% p.V1681_C1685del c. 5041 del15 1 0.28% - c. 5461-10T>C 24 6.63% - c. 5714+5 G>A 2 0.55% p.Pro1948Leu c. 5843 C>T 1 0.28% p.Gly1961Glu c. 5882 G>A 4 1.10% p.Leu2027Phe c.6079 C>T 30 8.29% p.Arg2030* c. 6088 C>T 1 0.28% p.Arg2030Gln c. 6089 G>A 3 0.83% p.Arg2038Trp c. 6112 C>T 1 0.28% p.Arg2107His c. 6320 G>A 2 0.55% p.Arg2118Glu fs*27 c. 6352 delA 1 0.28% p.Cys2150Tyr c. 6449 G>A 1 0.28% p.Gln2220* c. 6658 C>T 1 0.28% p.Gly863Ala mutation, which appears to have a founder effect in the Netherlands [13,15], the results obtained from the current study are in agreement with September et al.`s conclusions [9]. Login to comment

[hide] Familial discordance in Stargardt disease. Mol Vis. 2012;18:227-33. Epub 2012 Jan 28. Burke TR, Tsang SH, Zernant J, Smith RT, Allikmets R
Familial discordance in Stargardt disease.
Mol Vis. 2012;18:227-33. Epub 2012 Jan 28., [PMID:22312191]

Abstract [show]
PURPOSE: To report genetic and phenotypic discordance across two generations of a family with autosomal recessive Stargardt disease (STGD1) and to compare pathogenicities of the G1961E and A1038V alleles of the ATP-binding cassette transporter, subfamily A, member 4 (ABCA4) gene. METHODS: Five members of a family with STGD1 (patients 1-4, affected; patient 5, carrier) were included. Clinical assessment was performed together with fundus autofluorescence and spectral domain-optical coherence tomography. Patients were stratified based on the results of electroretinogram testing. Genotyping of the ABCA4 gene was performed with the ABCR500 microarray. RESULTS: STGD1 was diagnosed in the male proband and his female sibling (patients 1 and 2, respectively). Two children of patient 2 (patients 3 and 4) were also affected. Genotyping revealed the W663X stop mutation in all affected patients. Patients 3 and 4, who were compound heterozygous for the G1961E mutation, had earlier ages of onset than patients 1 and 2, who were compound heterozygous for the A1038V mutation. Patient 1 had an age of onset 28 years younger than patient 2, whose delayed onset can be explained by relative foveal sparing, while patient 4 had an age of onset 44 years younger than patient 2. CONCLUSIONS: The G1961E mutation, which has been considered "mild," yields a more severe phenotype in this family than the A1038V mutation, which has been considered "severe." Marked intrasibship discordance in clinical course is described, suggesting an additional role for modifying factors in ABCA4 pleiotropism.

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0 Familial discordance in Stargardt disease Tomas R. Burke,1,4 Stephen H. Tsang,1,2 Jana Zernant,1 R. Theodore Smith,1,3 Rando Allikmets1,2 1Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY; 2Department of Pathology and Cell Biology, Edward S. Harkness Eye Institute, Columbia University, New York, NY; 3Department of Biomedical Engineering, Columbia University, New York, NY; 4The Oxford Deanery, Prince Charles Eye Unit, King Edward VII Hospital, Windsor, United Kingdom Purpose: To report genetic and phenotypic discordance across two generations of a family with autosomal recessive Stargardt disease (STGD1) and to compare pathogenicities of the G1961E and A1038V alleles of the ATP-binding cassette transporter, subfamily A, member 4 (ABCA4) gene. Methods: Five members of a family with STGD1 (patients 1-4, affected; patient 5, carrier) were included. Clinical assessment was performed together with fundus autofluorescence and spectral domain-optical coherence tomography. Patients were stratified based on the results of electroretinogram testing. Login to comment
4 Patients 3 and 4, who were compound heterozygous for the G1961E mutation, had earlier ages of onset than patients 1 and 2, who were compound heterozygous for the A1038V mutation. Login to comment
5 Patient 1 had an age of onset 28 years younger than patient 2, whose delayed onset can be explained by relative foveal sparing, while patient 4 had an age of onset 44 years younger than patient 2. Conclusions: The G1961E mutation, which has been considered "mild," yields a more severe phenotype in this family than the A1038V mutation, which has been considered "severe." Login to comment
20 The W663X and A1038V mutations were detected in the ABCA4 gene in both patients 1 and 2, the latter having an onset of symptoms at 57 years of age i.e., 28 years later than her brother. Login to comment
28 DISCUSSION Both patients 1 and 2 were compound heterozygous for the W663X and A1038V mutations in the ABCA4 gene. Login to comment
29 W663X was previously reported as a disease-causing mutation [9]; it likely results in a completely dysfunctional protein due to the stop codon in the first 1/4 of the gene. A1038V, a missense mutation, is usually reported as a component of the complex allele L541P/A1038V, one of the most commonly detected mutations in the ABCA4 gene. A1038V is also known to be pathogenic without L541P as it has a deleterious effect on ATPase by ABCA4 in vitro [10,11]. Login to comment
30 While the complex allele gives rise to an ABCA4 protein which mislocalizes within the photoreceptor with a consequent reduction in protein function, the protein associated with A1038V alone does not demonstrate mislocalization [12]. Login to comment
32 The G1961E missense mutation, which has a deleterious effect on ABCA4`s ATPase activity, is the most common mutation detected in the ABCA4 gene and has been reported to confer a milder phenotype [11,16,17]. Login to comment
33 All affected patients in this family carried the W663X mutation, and although G1961E is considered a "mild" mutation, both patients with the G1961E mutation had earlier ages of onset than those with A1038V, which is considered "severe." Login to comment
34 A report by Cideciyan et al. describing age of disease onset in terms of "age of retina-wide disease initiation" (ADI) suggested that the G1961E mutation results in a much later ADI than the complex allele L541P/A1038V [18]. Login to comment
58 Qualitatively normal thickness RPE was also observed in regions with loss of IS/OS (F, white arrow).Corresponding size bars for A and B, C and D, and E and F are included in A, C and E, respectively Familial discordance in Stargardt disease Tomas R. Burke,1,4 Stephen H. Tsang,1,2 Jana Zernant,1 R. Theodore Smith,1,3 Rando Allikmets1,2 1Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY; 2Department of Pathology and Cell Biology, Edward S. Harkness Eye Institute, Columbia University, New York, NY; 3Department of Biomedical Engineering, Columbia University, New York, NY; 4The Oxford Deanery, Prince Charles Eye Unit, King Edward VII Hospital, Windsor, United Kingdom Purpose: To report genetic and phenotypic discordance across two generations of a family with autosomal recessive Stargardt disease (STGD1) and to compare pathogenicities of the G1961E and A1038V alleles of the ATP-binding cassette transporter, subfamily A, member 4 (ABCA4) gene. Methods: Five members of a family with STGD1 (patients 1-4, affected; patient 5, carrier) were included. Clinical assessment was performed together with fundus autofluorescence and spectral domain-optical coherence tomography. Patients were stratified based on the results of electroretinogram testing. Login to comment
62 Patients 3 and 4, who were compound heterozygous for the G1961E mutation, had earlier ages of onset than patients 1 and 2, who were compound heterozygous for the A1038V mutation. Login to comment
63 Patient 1 had an age of onset 28 years younger than patient 2, whose delayed onset can be explained by relative foveal sparing, while patient 4 had an age of onset 44 years younger than patient 2. Conclusions: The G1961E mutation, which has been considered "mild," yields a more severe phenotype in this family than the A1038V mutation, which has been considered "severe." Login to comment
19 The W663X and A1038V mutations were detected in the ABCA4 gene in both patients 1 and 2, the latter having an onset of symptoms at 57 years of age i.e., 28 years later than her brother. Login to comment
27 DISCUSSION Both patients 1 and 2 were compound heterozygous for the W663X and A1038V mutations in the ABCA4 gene. Login to comment
41 OD OS Patient #, sex Age at onset (years) Age at exam (years) Duration (years) ERG group VA GA area (mm 2 ) % change from baseline VA GA area (mm 2 ) % change from baseline Allele 1 Allele 2 1, M 29 63 34 I 20/125 7.5 20/150 7 W663X A1038V 64 35 20/150 8.1 0.067 20/150 7.3 0.047 65 36 20/150 9 0.186 20/200 7.9 0.139 2, F 57 68 11 I 20/25 0.4 20/40 1.5 W663X A1038V 69 12 20/30 0.5 0.309 20/30 1.7 0.167 3, M 21 41 20 I 20/150 10.8 20/150 5.8 W663X G1961E 4, F 13 39 26 I 20/150 2.2 20/150 6 W663X G1961E 40 27 20/150 2.9 0.183 20/150 7 0.109 5, M - 68 - - 20/20 - 20/20 - WT G1961E Figure 2. Login to comment

[hide] Transition zones between healthy and diseased reti... Invest Ophthalmol Vis Sci. 2011 Dec 20;52(13):9581-90. Print 2011. Lazow MA, Hood DC, Ramachandran R, Burke TR, Wang YZ, Greenstein VC, Birch DG
Transition zones between healthy and diseased retina in choroideremia (CHM) and Stargardt disease (STGD) as compared to retinitis pigmentosa (RP).
Invest Ophthalmol Vis Sci. 2011 Dec 20;52(13):9581-90. Print 2011., [PMID:22076985]

Abstract [show]
PURPOSE: To describe the structural changes across the transition zone (TZ) in choroideremia (CHM) and Stargardt disease (STGD) and to compare these to the TZ in retinitis pigmentosa (RP). METHODS: Frequency-domain (Fd)OCT line scans were obtained from seven patients with CHM, 20 with STGD, and 12 with RP and compared with those of 30 previously studied controls. A computer-aided manual segmentation procedure was used to determine the thicknesses of the outer segment (OS) layer, the outer nuclear layer plus outer plexiform layer (ONL+), the retinal pigment epithelium plus Bruch's membrane (RPE+BM), and the outer retina (OR). RESULTS: The TZ, while consistent within patient groups, showed differences across disease groups. In particular, (1) OS loss occurred before ONL+ loss in CHM and RP, whereas ONL+ loss occurred before OS loss in STGD; (2) ONL+ was preserved over a wider region of the retina in CHM than in RP; (3) RPE+BM remained normal across the RP TZ, but was typically thinned in CHM. In some CHM patients, it was abnormally thin in regions with normal OS and ONL+ thickness. In STGD, RPE+BM was thinned by the end of the TZ; and (4) the disappearances of the IS/OS and OLM were more abrupt in CHM and STGD than in RP. CONCLUSIONS: On fdOCT scans, patients with RP, CHM, and STGD all have a TZ between relatively healthy and severely affected retina. The patterns of changes in the receptor layers are similar within a disease category, but different across categories. The findings suggest that the pattern of progression of each disease is distinct and may offer clues for strategies in the development of future therapies.

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59 Characteristics of Patients with STGD Patient ID Eye Age Sex BCVA Mutation(s) (ABCA4) P8 12 OS 33 F 20/150 G1961E P9 2 OS 30 M 20/150 T1253M, G1961E P10 9817 OS 21 F 20/63 * P11 9 OS 19 M 20/150 IVS20ϩ5 GϾA, G1961E P12 6953 OD 49 F 20/50 * P13 11 OS 59 M 20/100 P1380L, S1696N P14 9831 OD 28 M 20/500 * P15 8813 OD 13 M 20/50 * P16 8 OS 34 M 20/100 G1961E, G1961E P17 6.1 OD 24 F 20/200 L541P/A1038V, G1961E P18 8833 OS 13 F 20/160 N965S, L2229P P19 8938 OD 13 M 20/200 A192T, R1300Q P20 5470 OD 28 F 20/100 * P21 9901 OS 41 M 20/160 I32V P22 9327 OS 11 F 20/63 G863A, A1695D P23 9386 OS 18 M 20/40 * P24 8862 OD 30 F 20/63 * P25 6.1 OD 21 F 20/150 L541P/A1038V, G1961E P26 6.2 OS 18 F 20/70 L541P/A1038V, G1961E P27 10 OS 23 F 20/150 L541P/A1038V, I1846T * Patient did not undergo genetic testing. Login to comment
31 Characteristics of Patients with STGD Patient ID Eye Age Sex BCVA Mutation(s) (ABCA4) P8 12 OS 33 F 20/150 G1961E P9 2 OS 30 M 20/150 T1253M, G1961E P10 9817 OS 21 F 20/63 * P11 9 OS 19 M 20/150 IVS20af9;5 Gb0e;A, G1961E P12 6953 OD 49 F 20/50 * P13 11 OS 59 M 20/100 P1380L, S1696N P14 9831 OD 28 M 20/500 * P15 8813 OD 13 M 20/50 * P16 8 OS 34 M 20/100 G1961E, G1961E P17 6.1 OD 24 F 20/200 L541P/A1038V, G1961E P18 8833 OS 13 F 20/160 N965S, L2229P P19 8938 OD 13 M 20/200 A192T, R1300Q P20 5470 OD 28 F 20/100 * P21 9901 OS 41 M 20/160 I32V P22 9327 OS 11 F 20/63 G863A, A1695D P23 9386 OS 18 M 20/40 * P24 8862 OD 30 F 20/63 * P25 6.1 OD 21 F 20/150 L541P/A1038V, G1961E P26 6.2 OS 18 F 20/70 L541P/A1038V, G1961E P27 10 OS 23 F 20/150 L541P/A1038V, I1846T * Patient did not undergo genetic testing. Login to comment

[hide] Quantification of peripapillary sparing and macula... Invest Ophthalmol Vis Sci. 2011 Oct 10;52(11):8006-15. Print 2011. Burke TR, Rhee DW, Smith RT, Tsang SH, Allikmets R, Chang S, Lazow MA, Hood DC, Greenstein VC
Quantification of peripapillary sparing and macular involvement in Stargardt disease (STGD1).
Invest Ophthalmol Vis Sci. 2011 Oct 10;52(11):8006-15. Print 2011., [PMID:21873672]

Abstract [show]
PURPOSE: To quantify and compare structure and function across the macula and peripapillary area in Stargardt disease (STGD1). METHODS: Twenty-seven patients (27 eyes) and 12 age-similar controls (12 eyes) were studied. Patients were classified on the basis of full-field electroretinogram (ERG) results: Fundus autofluorescence (FAF) and spectral domain-optical coherence tomography (SD-OCT) horizontal line scans were obtained through the fovea and peripapillary area. The thicknesses of the outer nuclear layer plus outer plexiform layer (ONL+), outer segment (OS), and retinal pigment epithelium (RPE) were measured through the fovea, and peripapillary areas from 1 degrees to 4 degrees temporal to the optic disc edge using a computer-aided, manual segmentation technique. Visual sensitivities in the central 10 degrees were assessed using microperimetry and related to retinal layer thicknesses. RESULTS: Compared to the central macula, the differences between controls and patients in ONL+, OS, and RPE layer thicknesses were less in the nasal and temporal macula. Relative sparing of the ONL+ and/or OS layers was detected in the nasal (i.e., peripapillary) macula in 8 of 13 patients with extramacular disease on FAF; relative functional sparing was also detected in this subgroup. All 14 patients with disease confined to the central macula, as detected on FAF, showed ONL+ and OS layer thinning in regions of normal RPE thickness. CONCLUSIONS: Relative peripapillary sparing was detected in STGD1 patients with extramacular disease on FAF. Photoreceptor thinning may precede RPE degeneration in STGD1.

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112 Summary of Clinical, Demographic, and Genetic Data Patient Sex Age at Exam (y) Eye VA BCEA 1 SD (deg 2 ) Eccentricity of PRL (deg) ERG Group FAF Abnormalities Allele 1 Allele 2 Allele 3 Distribution Peripapillary Area 1 F 43 OS 20/20 0.73 0 II M - A1799D ND ND 2 M 30 OS 20/150 3.21 6 I M - T1253M G1961E ND 3 F 55 OD 20/30 1.82 0 I EM - G863A IVS28af9;5 Gb0e;T ND 4 M 44 OD 20/25 0.65 0 I M - E161K ND ND 5.1 F 24 OD 20/200 1.57 1 I M - L541P/A1038V G1961E ND 5.2 F 22 OD 20/30 2.74 1 I M - L541P/A1038V G1961E ND 6.1 F 21 OD 20/150 2.01 1 I M - L541P/A1038V G1961E ND 6.2 F 18 OS 20/100 3.09 4 I M - L541P/A1038V G1961E ND 7 F 27 OS 20/400 2.97 9* II EM Peripapillary atrophy L2027F G851D ND 8 M 34 OS 20/100 2.16 4 I M - G1961E G1961E ND 9 M 20 OS 20/150 2.77 4 I M - IVS20af9;5 Gb0e;A G1961E ND 10 F 23 OS 20/150 9.05 5 I M - L541P/A1038V I1846T ND 11 M 59 OS 20/100 6.52 10 II EM - P1380L S1696N ND 12 M 49 OD 20/150 9.97 1 I EM Nasalaf9;temporal flecks R1108H P1380L ND 13 M 47 OS 20/80 5.62 7 I EM - G863A Y106X ND 14 F 42 OD 20/200 9.53 9 I EM Temporal flecks N965S ND ND 15 M 14 OD 20/200 23.84 1 II EM Nasal flecks IVS38-10 Tb0e;C IVS40af9;5 Gb0e;A ND 16 M 52 OS 20/20 1.3 0 I M - IVS38-10 Tb0e;C ND ND 17 M 34 OS 20/30 2.8 1 I M - L541P/A1038V G1961E ND 18 F 33 OD 20/100 6 6 I M - G1961E R2077W ND 19 F 22 OS 20/60 11 4 I M - A854T A1038V C2150Y 20 F 34 OS 20/200 14.2 14 I EM - G1961E ND ND 21 F 19 OD 20/200 3.7 12 I EM - R602W M18821 ND 22 F 27 OD 20/400 9.6 9 II EM Peripapillary atrophy P1380L P1380L ND 23 F 18 OS 20/50 4.9 5 I EM - R1640W V1693I ND 24 M 22 OS 20/150 10.5 2 I EM - C54Y ND ND 25 M 44 OS 20/150 9.1 5 I EM - R1640W ND ND VA, visual acuity; Rel. Login to comment

[hide] Deducing the pathogenic contribution of recessive ... Hum Mol Genet. 2010 Oct 1;19(19):3693-701. Epub 2010 Jul 20. Schindler EI, Nylen EL, Ko AC, Affatigato LM, Heggen AC, Wang K, Sheffield VC, Stone EM
Deducing the pathogenic contribution of recessive ABCA4 alleles in an outbred population.
Hum Mol Genet. 2010 Oct 1;19(19):3693-701. Epub 2010 Jul 20., [PMID:20647261]

Abstract [show]
Accurate prediction of the pathogenic effects of specific genotypes is important for the design and execution of clinical trials as well as for meaningful counseling of individual patients. However, for many autosomal recessive diseases, it can be difficult to deduce the relative pathogenic contribution of individual alleles because relatively few affected individuals share the same two disease-causing variations. In this study, we used multiple regression analysis to estimate the pathogenicity of specific alleles of ABCA4 in patients with retinal phenotypes ranging from Stargardt disease to retinitis pigmentosa. This analysis revealed quantitative allelic effects on two aspects of the visual phenotype, visual acuity (P < 10(-3)) and visual field (P < 10(-7)). Discordance between visual acuity and visual field in individual patients suggests the existence of at least two non-ABCA4 modifying factors. The findings of this study will facilitate the discovery of factors that modify ABCA4 disease and will also aid in the optimal selection of subjects for clinical trials of new therapies.

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54 Allele VF model Acuity model Occurrences Groupa Leu2027Phe 22.81 0.14 4 a Leu1201Arg 22.29 0.16 2 a Met316fs 20.71 20.15 4 a Gly1961Glu 18.08 0.26 8 a Gly863Ala 16.54 0.36 19 a Pro1380Leu 15.88 0.39 10 a Ala1038Val 15.19 20.03 12 a Leu541Pro 10.95 0.08 1 b Asn965Ser 9.3 0.07 3 b IVS40 + 5 9.29 0.22 9 b Val256Val 9.27 0.84 2 b Phe608Ile 7.24 0.48 2 b IVS38-10 5.75 0.37 14 b Arg1108Cys 1.29 0.81 6 b Leu1430fs 0.37 0.6 2 b Arg2077Trp 26.89 0.93 4 b a When analyzed as groups, A alleles have significantly milder effects on both visual acuity (P , 1023 ) and visual field (P , 1027 ) than B alleles (see text). Login to comment
57 Allele VF model Acuity model Occurrences Groupa Leu2027Phe 22.81 0.14 4 a Leu1201Arg 22.29 0.16 2 a Met316fs 20.71 20.15 4 a Gly1961Glu 18.08 0.26 8 a Gly863Ala 16.54 0.36 19 a Pro1380Leu 15.88 0.39 10 a Ala1038Val 15.19 20.03 12 a Leu541Pro 10.95 0.08 1 b Asn965Ser 9.3 0.07 3 b IVS40 + 5 9.29 0.22 9 b Val256Val 9.27 0.84 2 b Phe608Ile 7.24 0.48 2 b IVS38-10 5.75 0.37 14 b Arg1108Cys 1.29 0.81 6 b Leu1430fs 0.37 0.6 2 b Arg2077Trp 26.89 0.93 4 b a When analyzed as groups, A alleles have significantly milder effects on both visual acuity (P , 1023 ) and visual field (P , 1027 ) than B alleles (see text). Login to comment

[hide] Analysis of autofluorescent retinal images and mea... Exp Eye Res. 2010 Aug;91(2):143-52. Epub 2010 Apr 14. Chen B, Tosha C, Gorin MB, Nusinowitz S
Analysis of autofluorescent retinal images and measurement of atrophic lesion growth in Stargardt disease.
Exp Eye Res. 2010 Aug;91(2):143-52. Epub 2010 Apr 14., [PMID:20398653]

Abstract [show]
Current retinal imaging techniques using scanning laser ophthalmoscopy (SLO) provide a powerful mechanism for characterizing the topographical distribution of lipofuscin fluorophores and atrophic lesions (ALs) in retinal disease. In this paper we describe a novel Edge-Flow-Driven Variational Image Segmentation analysis to measure and evaluate progressive change in the area of ALs as well as regions of hyperfluorescence (HF). The algorithm is embedded in a series of almost completely automated image processing steps that allow rapid comparison of serial images. The sensitivity of the methodology to detect change was evaluated by measuring progression of AF lesion size in a cohort of Stargardt Macular Dystrophy (STGD) patients. Fifty-two STGD subjects (mean age = 41.0 +/- 16.6 years, range 9-78 yrs) at varying stages of disease participated in this prospective study. Twenty-four of the 52 subjects presented with atrophic lesions in one or both eyes on first evaluation. For this subgroup of subjects, the mean (+/-1 sd) follow-up time was 2.92 (+0.26) years (range 0.57-3.26 years) and the mean (+/-1 sd) rate of change was found to be approximately 0.94 (+/-0.87) mm(2)/year (range 0.2-2.13 mm(2)/yr). With this methodology, progressive enlargement of AL area was detectable in as little as one year, while regions of HF generally decreased, although there was considerable variability in the appearnce of HF, presumably reflecting the combined effects of the creation or expansion of lipofuscin deposits and resorption and loss associated with retinal cell death. Our findings suggest that this methodology is sufficiently sensitive to detect change and provides a clinically relevant tool to monitor progression not only with regards to natural history, but also to evaluate the efficacy of potential therapeutic interventions in STGD. Finally, we evaluated the association between AL area and measures of rod- and cone-mediated retinal function, as assessed with electroretinography (ERG). In general, the larger the AL, the poorer the ERG response, with a greater impact of lesion size on cone- rather than rod-mediated retinal function, a finding that was expected on the basis of the location and size of the AL and the distribution of rod- and cone-photoreceptors.

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82 ID# Age Years followed Visual Acuity AL Area (mm2 ) HF Area (mm2 ) ffERG Amplitudes (mV) ffERG IT (msec) ABCA4 Variants OD OS OD OS OD OS OD OS OD OS Rod Cone Rod Cone Rod Cone Rod Cone AI AII Group A S0047 53 2.83 20/40 20/40 31.60 33.85 0.20 0.07 304.0 125.4 392.9 143.3 69.5 29.3 72.7 29.3 NF NF S0023 49 3.26 20/160 20/160 9.92 12.67 1.24 1.49 292.1 52.2 272.4 46.4 77.9 36.8 78.3 35.2 L541P/A1038V NF S0050 78 2.71 20/250 20/160 2.02 0.07 1.21 0.67 355.0 82.2 373.1 87.2 76.7 34.1 76.7 34.8 S2255I IVS5,þ1,G > C S0045 44 3.16 20/200 20/160 17.27 44.72 NM NM 177.0 55.7 201.9 50.0 85.3 41.5 87.7 39.9 L541P/A1038V R2107K S0018 35 2.28 20/200 20/250 4.31 2.53 NM NM ND ND ND ND ND ND ND ND G1961E S2255I S0033 63 2.35 20/800 20/400 15.51 12.09 1.30 0.22 168.2 53.0 180.9 45.4 96.3 38.0 101.0 38.4 R943Q IVS8,-9, T > C S0048 62 2.56 20/80 20/20 48.45 40.73 NM NM 119.7 69.5 213.9 54.6 71.2 35.6 80.6 35.2 R290Q K346T S0036 62 2.81 20/640 20/500 55.70 43.38 NM NM 174.8 41.1 158.1 50.8 106.6 38.5 102.3 35.2 R1129L Q234X S0029 62 2.81 20/40 20/80 57.62 61.25 NM NM 219.0 26.0 209.2 35.2 77.9 31.3 73.6 30.9 R2030Q NF S0024 43 3.20 20/25 20/25 4.91 3.91 4.18 1.48 98.2 23.7 148.0 36.2 84.0 33.2 85.5 33.6 NF NF S0078 35 1.17 20/100 20/125 5.64 5.39 0.70 0.83 230.1 106.7 187.6 108.8 71.2 34.1 64.6 34.1 IVS39-10,T > C NF S0032 64 2.56 20/250 20/320 8.67 3.67 0.67 0.74 273.2 75.5 235.1 114.7 87.9 30.5 72.7 30.1 R1108C L2027F S0051 52 1.90 20/25 20/20 32.78 29.23 NM NM ND ND ND ND ND ND ND ND E471K NF S0115 16 0.57 20/50 20/50 0.77 3.43 NM NM ND ND ND ND ND ND ND ND NF NF S0077 49 1.14 20/40 20/25 N/A 8.54 0.16 1.89 279.9 111.9 299.3 105.2 N/A N/A N/A N/A NF NF S0042 43 1.84 20/125 20/200 118.15 126.69 NM NM 122.3 27.7 114.8 29.3 85.7 36.4 89.6 36.0 S2255I E471K S0037 46 2.38 20/125 20/200 8.73 N/A 1.29 0.86 338.7 119.3 373.7 109.4 72.3 28.1 70.7 28.1 G1961E S2255I S0020 42 0.0 20/200 20/160 1.16 1.82 NM NM 140.4 43.2 159.9 45.8 81.3 31.3 71.5 29.3 NF NF S0041 44 0.0 20/200 20/160 4.73 7.09 0.96 1.36 260.5 65* 297.2 95.3 113.7 29.7 91.8 28.9 R1129L NF S0087 44 0.0 20/20 20/20 14.89 23.09 NM NM 180.9 66.8 182.2 78.0 76.1 32.9 72.2 32.9 IVS40, þ5,G > A NF S0053 43 0.0 20/100 20/160 1.33 1.85 NM NM ND ND ND ND ND ND ND ND S2255I NF S0097 73 0.0 20/200 20/200 49.21 54.26 NM NM ND ND ND ND ND ND ND ND D1532E NF S0080 28 0.0 20/125 20/200 NA 0.98 0.56 0.03 333.1 117.2 325.1 121.4 80.2 32.5 82.6 32.9 E1122K S2255I S0210 49 0.0 20/160 20/200 0.21 NA NM NM 304.1 76.1 425.7 81.1 72.8 33.7 79.8 33.7 NF NF Group B S0133 30 0.0 20/125 20/32 0.51 0.01 387.1 123.7 374.8 105.1 65.4 32.9 65.0 32.9 NF NF S0046 49 0.0 20/160 20/160 1.48 1.68 491.2 148.9 494.9 145.3 72.7 30.1 77.3 29.7 P1380L G1961E S0141 40 0.0 20/13 20/32 1.88 0.41 389.0 156.5 343.5 150.6 70.8 33.3 69.7 34.4 NF NF S0058 61 0.0 20/50 20/50 1.48 1.52 ND ND ND ND ND ND ND ND NF NF S0149 16 0.0 20/80 20/100 1.59 0.62 285.0 87.4 333.4 115.3 62.6 32.5 61.4 32.5 NF NF S0083 15 0.0 20/13 20/13 0.17 0.48 441.1 144.2 472.0 155.5 74.4 33.3 71.6 33.3 G863A NF S0216 44 0.0 20/25 20/32 0.52 1.04 228.7 97.7 192.7 75.3 83.8 36.8 85.7 36.0 NF NF S0076 9 0.0 20/200 20/160 3.70 4.23 557.7 139.5 319.8 117.3 81.6 29.7 73.4 28.9 W1408R T1526M S0021 19 0.0 20/160 20/160 1.81 1.08 390.4 202.1 ND ND 63.3 29.3 ND ND L2027F W31R S0085 35 0.0 20/16 20/20 2.70 2.56 ND ND ND ND ND ND ND ND C54T R219T S0044 30 0.0 20/250 20/250 4.23 3.77 ND ND ND ND ND ND ND ND A1794D L2027F S0035 47 0.0 20/160 20/125 0.46 0.13 239.6 112.3 325.0 141.6 64.1 28.1 62.5 28.1 G863A E471K S0065 61 0.0 20/100 20/125 0.83 0.15 243.4 58.6 226.5 49.2 74.8 32.9 84.5 33.3 G1961E NF S0213 27 0.0 20/25 20/25 0.99 1.03 384.2 124.4 424.4 137.9 72.4 31.7 72.4 35.2 NF NF S0088 55 0.0 20/25 20/20 0.11 0.47 ND ND ND ND ND ND ND ND R1898H NF S0127 16 0.0 20/63 20/63 0.08 0.69 536.3 128.9 470.3 136.4 65.4 30.9 77.1 30.9 L541P/A1038V NF S0057 47 0.48 20/125 20/160 1.20 1.75 252.1 80.3 210.5 100.5 75.5 32.9 89.6 32.5 NF NF S0043 53 2.91 20/200 20/200 0.97 0.53 250.5 173.2 354.6 179.2 72.7 28.5 80.1 30.1 G1961E F873I S0101 37 1.1 20/40 20/20 0.14 0.25 382.2 159.7 422.7 156.7 70.5 32.5 74.0 32.9 A1038V IVS42 þ 1,G > A S0027 17 2.18 20/50 20/50 1.60 2.12 196.3 36.3 198.0 51.0 84.7 32.9 98.8 35.3 NF NF S0104 20 1.19 20/160 20/200 0.05 0.12 237.4 77.7 440.1 88.7 63.0 30.9 64.6 30.1 NF NF S0110 26 1.02 20/200 20/125 0.65 0.56 333.8 94.5 349.4 98.7 68.9 32.1 68.9 32.5 R1129L NF S0049 34 2.13 20/50 20/200 0.76 0.92 374.4 97.2 344.0 90.5 81.0 32.9 65.8 33.7 R1129L NF S0075 22 1.06 20/63 20/125 0.40 0.69 454.5 114.0 452.7 122.8 77.5 32.1 75.5 32.9 G1961E NF S0039 36 2.2 20/160 20/100 0.15 0.13 347.7 137.1 395.8 142.0 80.1 31.3 61.7 30.9 M1V R2107H S0054 31 1.93 20/40 20/40 0.41 0.56 ND ND ND ND ND ND ND ND G1961E S2255I S0040 11 2.97 20/160 20/160 0.46 0.07 610.2 72.5 375.6 67.4 106.5 37.2 93.5 32.9 R572X N1805D S0028 54 2.73 20/16 20/16 1.04 1.54 425.5 105.8 386.3 107.8 83.4 34.4 84.1 34.8 L541P/A1038V R2030Q ND ¼ not done. Login to comment
81 ID# Age Years followed Visual Acuity AL Area (mm2 ) HF Area (mm2 ) ffERG Amplitudes (mV) ffERG IT (msec) ABCA4 Variants OD OS OD OS OD OS OD OS OD OS Rod Cone Rod Cone Rod Cone Rod Cone AI AII Group A S0047 53 2.83 20/40 20/40 31.60 33.85 0.20 0.07 304.0 125.4 392.9 143.3 69.5 29.3 72.7 29.3 NF NF S0023 49 3.26 20/160 20/160 9.92 12.67 1.24 1.49 292.1 52.2 272.4 46.4 77.9 36.8 78.3 35.2 L541P/A1038V NF S0050 78 2.71 20/250 20/160 2.02 0.07 1.21 0.67 355.0 82.2 373.1 87.2 76.7 34.1 76.7 34.8 S2255I IVS5,&#fe;1,G > C S0045 44 3.16 20/200 20/160 17.27 44.72 NM NM 177.0 55.7 201.9 50.0 85.3 41.5 87.7 39.9 L541P/A1038V R2107K S0018 35 2.28 20/200 20/250 4.31 2.53 NM NM ND ND ND ND ND ND ND ND G1961E S2255I S0033 63 2.35 20/800 20/400 15.51 12.09 1.30 0.22 168.2 53.0 180.9 45.4 96.3 38.0 101.0 38.4 R943Q IVS8,-9, T > C S0048 62 2.56 20/80 20/20 48.45 40.73 NM NM 119.7 69.5 213.9 54.6 71.2 35.6 80.6 35.2 R290Q K346T S0036 62 2.81 20/640 20/500 55.70 43.38 NM NM 174.8 41.1 158.1 50.8 106.6 38.5 102.3 35.2 R1129L Q234X S0029 62 2.81 20/40 20/80 57.62 61.25 NM NM 219.0 26.0 209.2 35.2 77.9 31.3 73.6 30.9 R2030Q NF S0024 43 3.20 20/25 20/25 4.91 3.91 4.18 1.48 98.2 23.7 148.0 36.2 84.0 33.2 85.5 33.6 NF NF S0078 35 1.17 20/100 20/125 5.64 5.39 0.70 0.83 230.1 106.7 187.6 108.8 71.2 34.1 64.6 34.1 IVS39-10,T > C NF S0032 64 2.56 20/250 20/320 8.67 3.67 0.67 0.74 273.2 75.5 235.1 114.7 87.9 30.5 72.7 30.1 R1108C L2027F S0051 52 1.90 20/25 20/20 32.78 29.23 NM NM ND ND ND ND ND ND ND ND E471K NF S0115 16 0.57 20/50 20/50 0.77 3.43 NM NM ND ND ND ND ND ND ND ND NF NF S0077 49 1.14 20/40 20/25 N/A 8.54 0.16 1.89 279.9 111.9 299.3 105.2 N/A N/A N/A N/A NF NF S0042 43 1.84 20/125 20/200 118.15 126.69 NM NM 122.3 27.7 114.8 29.3 85.7 36.4 89.6 36.0 S2255I E471K S0037 46 2.38 20/125 20/200 8.73 N/A 1.29 0.86 338.7 119.3 373.7 109.4 72.3 28.1 70.7 28.1 G1961E S2255I S0020 42 0.0 20/200 20/160 1.16 1.82 NM NM 140.4 43.2 159.9 45.8 81.3 31.3 71.5 29.3 NF NF S0041 44 0.0 20/200 20/160 4.73 7.09 0.96 1.36 260.5 65* 297.2 95.3 113.7 29.7 91.8 28.9 R1129L NF S0087 44 0.0 20/20 20/20 14.89 23.09 NM NM 180.9 66.8 182.2 78.0 76.1 32.9 72.2 32.9 IVS40, &#fe;5,G > A NF S0053 43 0.0 20/100 20/160 1.33 1.85 NM NM ND ND ND ND ND ND ND ND S2255I NF S0097 73 0.0 20/200 20/200 49.21 54.26 NM NM ND ND ND ND ND ND ND ND D1532E NF S0080 28 0.0 20/125 20/200 NA 0.98 0.56 0.03 333.1 117.2 325.1 121.4 80.2 32.5 82.6 32.9 E1122K S2255I S0210 49 0.0 20/160 20/200 0.21 NA NM NM 304.1 76.1 425.7 81.1 72.8 33.7 79.8 33.7 NF NF Group B S0133 30 0.0 20/125 20/32 0.51 0.01 387.1 123.7 374.8 105.1 65.4 32.9 65.0 32.9 NF NF S0046 49 0.0 20/160 20/160 1.48 1.68 491.2 148.9 494.9 145.3 72.7 30.1 77.3 29.7 P1380L G1961E S0141 40 0.0 20/13 20/32 1.88 0.41 389.0 156.5 343.5 150.6 70.8 33.3 69.7 34.4 NF NF S0058 61 0.0 20/50 20/50 1.48 1.52 ND ND ND ND ND ND ND ND NF NF S0149 16 0.0 20/80 20/100 1.59 0.62 285.0 87.4 333.4 115.3 62.6 32.5 61.4 32.5 NF NF S0083 15 0.0 20/13 20/13 0.17 0.48 441.1 144.2 472.0 155.5 74.4 33.3 71.6 33.3 G863A NF S0216 44 0.0 20/25 20/32 0.52 1.04 228.7 97.7 192.7 75.3 83.8 36.8 85.7 36.0 NF NF S0076 9 0.0 20/200 20/160 3.70 4.23 557.7 139.5 319.8 117.3 81.6 29.7 73.4 28.9 W1408R T1526M S0021 19 0.0 20/160 20/160 1.81 1.08 390.4 202.1 ND ND 63.3 29.3 ND ND L2027F W31R S0085 35 0.0 20/16 20/20 2.70 2.56 ND ND ND ND ND ND ND ND C54T R219T S0044 30 0.0 20/250 20/250 4.23 3.77 ND ND ND ND ND ND ND ND A1794D L2027F S0035 47 0.0 20/160 20/125 0.46 0.13 239.6 112.3 325.0 141.6 64.1 28.1 62.5 28.1 G863A E471K S0065 61 0.0 20/100 20/125 0.83 0.15 243.4 58.6 226.5 49.2 74.8 32.9 84.5 33.3 G1961E NF S0213 27 0.0 20/25 20/25 0.99 1.03 384.2 124.4 424.4 137.9 72.4 31.7 72.4 35.2 NF NF S0088 55 0.0 20/25 20/20 0.11 0.47 ND ND ND ND ND ND ND ND R1898H NF S0127 16 0.0 20/63 20/63 0.08 0.69 536.3 128.9 470.3 136.4 65.4 30.9 77.1 30.9 L541P/A1038V NF S0057 47 0.48 20/125 20/160 1.20 1.75 252.1 80.3 210.5 100.5 75.5 32.9 89.6 32.5 NF NF S0043 53 2.91 20/200 20/200 0.97 0.53 250.5 173.2 354.6 179.2 72.7 28.5 80.1 30.1 G1961E F873I S0101 37 1.1 20/40 20/20 0.14 0.25 382.2 159.7 422.7 156.7 70.5 32.5 74.0 32.9 A1038V IVS42 &#fe; 1,G > A S0027 17 2.18 20/50 20/50 1.60 2.12 196.3 36.3 198.0 51.0 84.7 32.9 98.8 35.3 NF NF S0104 20 1.19 20/160 20/200 0.05 0.12 237.4 77.7 440.1 88.7 63.0 30.9 64.6 30.1 NF NF S0110 26 1.02 20/200 20/125 0.65 0.56 333.8 94.5 349.4 98.7 68.9 32.1 68.9 32.5 R1129L NF S0049 34 2.13 20/50 20/200 0.76 0.92 374.4 97.2 344.0 90.5 81.0 32.9 65.8 33.7 R1129L NF S0075 22 1.06 20/63 20/125 0.40 0.69 454.5 114.0 452.7 122.8 77.5 32.1 75.5 32.9 G1961E NF S0039 36 2.2 20/160 20/100 0.15 0.13 347.7 137.1 395.8 142.0 80.1 31.3 61.7 30.9 M1V R2107H S0054 31 1.93 20/40 20/40 0.41 0.56 ND ND ND ND ND ND ND ND G1961E S2255I S0040 11 2.97 20/160 20/160 0.46 0.07 610.2 72.5 375.6 67.4 106.5 37.2 93.5 32.9 R572X N1805D S0028 54 2.73 20/16 20/16 1.04 1.54 425.5 105.8 386.3 107.8 83.4 34.4 84.1 34.8 L541P/A1038V R2030Q ND &#bc; not done. Login to comment

[hide] Novel mutations in of the ABCR gene in Italian pat... Eye (Lond). 2010 Jan;24(1):158-64. Epub 2009 Mar 6. Passerini I, Sodi A, Giambene B, Mariottini A, Menchini U, Torricelli F
Novel mutations in of the ABCR gene in Italian patients with Stargardt disease.
Eye (Lond). 2010 Jan;24(1):158-64. Epub 2009 Mar 6., [PMID:19265867]

Abstract [show]
PURPOSE: Stargardt disease (STGD) is the most prevalent juvenile macular dystrophy, and it has been associated with mutations in the ABCR gene, encoding a photoreceptor-specific transport protein. In this study, we determined the mutation spectrum in the ABCR gene in a group of Italian STGD patients. METHODS: The DNA samples of 71 Italian patients (from 62 independent pedigrees), affected with autosomal recessive STGD, were analysed for mutations in all 50 exons of the ABCR gene by the DHPLC approach (with optimization of the DHPLC conditions for mutation analysis) and direct sequencing techniques. RESULTS: In our group of STGD patients, 71 mutations were identified in 68 patients with a detection rate of 95.7%. Forty-three mutations had been already reported in the literature, whereas 28 mutations had not been previously described and were not detected in 150 unaffected control individuals of Italian origin. Missense mutations represented the most frequent finding (59.2%); G1961E was the most common mutation and it was associated with phenotypes in various degrees of severity. CONCLUSIONS: Some novel mutations in the ABCR gene were reported in a group of Italian STGD patients confirming the extensive allelic heterogeneity of this gene-probably related to the vast number of exons that favours rearrangements in the DNA sequence.

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57 Table 2 Summary of the mutations identified in the ABCR gene in our series of STGD Italian patients Patient Allele 1 mutation Allele 2 mutation S 1 R212C T1019M S 8 V1433I V1433I S 21 A1598D A1598D S 33 N96K G978D S 56 A1598D G1961E S 70 R212C T1019M S 71 W700X WT S 74 6750delA V767D S 77 G1961E WT S 82 Q21X G1961E S 106 C1177X G1961E S 107 C1177X G1961E S 114 T970P-F1015E - S 115 T970P-F1015E - S 120 N415K G1961E S 162 324-327insT 324-327insT S 181 W1408X G1961E S 190 C1177X A1598D S 201 G1961E WT S 202 Q21X T970P-F1015E S 213 M840R G1961E S 231 WT WT S 236 C1177X G1961E S 237 WT WT S 241 V256 splice WT S 246 IVS6-1g4t R1108C S 260 L2221P 5109delG-I156V S 321 IVS9 þ 1G4C S1099X S 328 IVS42 þ 4delG IVS35 þ 2t4c S 346 E2096K WT S 347 IVS28 þ 5g4a WT S 353 P1484S-G1961E P68L S 354 P1484S-G1961E P68L S 355 P1484S-G1961E P68L S 360 G1961E 5961delGGAC S 364 IVS35 þ 2t4c G1961E S 365 L541P/A1038V G1961E S 377 IVS42 þ 4delG IVS35 þ 2t4c S 380 R653C WT S 413 R212C T1019M S 414 A1598D G1961E S 417 G1078E G1961E S 438 R1055W WT S 440 4021ins24bp T1526M-G1961E S 449 W1479X L2140Q S 450 W1479X L2140Q S 474 W1461X G 1977S S 486 WT WT S 492 R1098C/L1970F 6548insTGAA S 528 T977P IVS40 þ 5g4a S 531 G690V Q1332X S 532 R572X L1473M-4733delGTTT S 535 IVS40 þ 5g4a 5917delG S 550 IVS40 þ 5g4a 6750delA S 555 250insCAAA WT S 556 250insCAAA WT S 575 N96H G1961E S 590 W821R IVS40 þ 5g4a S 592 V931M R1108C S 593 V767D R2030X Table 2 (Continued ) Patient Allele 1 mutation Allele 2 mutation S 594 G172S G1961E S 602 P1380L G1961E S 607 E616K L1580S-K2172R S 640 250insCAAA S1696N S 694 IVS35 þ 2t4c G1961E S 725 IVS13 þ 1g4a Q1376 splice S 731 L541P-A1038V G1961E S 755 N965S IVS40 þ 5g4a S 789 E1087K G1977S S 968 T1019M G1961E S 992 R212C G1961E Bold values indicate novel mutations. Login to comment
85 Therefore, it can be speculated that its clinical expression depends on the mutation severity on the fellow allele, as suggested by earlier genotype/ phenotype studies.17,21 Still, although the A1038V mutation is commonly reported in the literature,9,13,27 in our series, it was detected in only two patients (1.4% of the patients, 0.7% of the alleles) within the L541P-A1038V complex allele. Login to comment

[hide] ABC transporters in ophthalmic disease. Methods Mol Biol. 2010;637:221-30. Westerfeld C
ABC transporters in ophthalmic disease.
Methods Mol Biol. 2010;637:221-30., [PMID:20419437]

Abstract [show]
ABC transporters have been implicated in a variety of human diseases. The ABCR gene and its protein have been linked to Stargardt's disease, fundus flavimaculatus, cone-rod dystrophy, retinitis pigmentosa, and age-related macular degeneration. The genetic and molecular pathways involved in the pathogenesis of ABCR-related ophthalmic conditions will be explored. Future diagnostic and therapeutic objectives for these diseases will also be discussed.

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38 Certain mutant alleles such as G863A, A1038V, and G1961E cause Stargardt`s disease and appear to be more common and may have altered frequencies in different populations, presumably because of founder effect (23, 24). Login to comment

[hide] The natural history of stargardt disease with spec... Invest Ophthalmol Vis Sci. 2009 Dec;50(12):5867-71. Epub 2009 Jul 2. Genead MA, Fishman GA, Stone EM, Allikmets R
The natural history of stargardt disease with specific sequence mutation in the ABCA4 gene.
Invest Ophthalmol Vis Sci. 2009 Dec;50(12):5867-71. Epub 2009 Jul 2., [PMID:19578016]

Abstract [show]
PURPOSE: To determine longitudinal changes in fundus appearance and visual function in patients with Stargardt with at least one allelic mutation (Gly1961Glu) in the ABCA4 gene. METHODS: Sixteen patients with a diagnosis of Stargardt disease and a Gly1961Glu mutation were enrolled. All patients underwent a complete ocular examination including best corrected visual acuity, Goldmann visual field (GVF), and full-field ERG examinations. The percentage of patients who showed at least a doubling in the log of the minimum angle of visual resolution (logMAR) between their initial and most recent visits was determined, as was the percentage of patients who showed a doubling in the size of the central scotoma over this duration. RESULTS: Nine patients had at least a doubling of the logMAR visual acuity in their right eyes and 10 patients in their left eyes, over a mean follow-up (FU) period of 18.6 years. Of 15 patients, 46.7% had equal to or more than a doubling of the central scotoma area in response to a II2e test stimulus in the right eye and 60.0% in the left eyes. Among 10 patients whose ERGs were initially normal for rod and cone responses, 8 remained normal at their most recent FU visit. CONCLUSIONS: In these patients with Stargardt disease and a Gly1961Glu mutation, most showed a clinical phenotype characterized by fundus changes localized to the foveal and parafoveal regions, normal ERG amplitudes, absence of a silent or masked choroid, and a mean age at initial presentation in the third decade.

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66 Genetic Mutations in the ABCA4 Gene in the Patients Patient No. Genetic Mutation Allele 1 Genetic Mutation Allele 2 Comments 1 gly1961glu exon 42 Heterozygous 2 gly1961glu exon 42 ala1038val exon 21 and leu541pro exon 12 Compound heterozygous 3 gly1961glu exon 42 Heterozygous 4 gly1961glu exon 42 arg2077trp exon 45 Compound heterozygous 5 gly1961glu exon 42 gly65glu exon 3 Compound heterozygous 6 gly1961glu exon 42 leu1201arg exon 24 Compound heterozygous 7 gly1961glu exon 42 Heterozygous 8 gly1961glu exon 42 Heterozygous 9 gly1961glu exon 42 del Co 1620-1622 exon 35 Compound heterozygous 10 gly1961glu exon 42 Heterozygous 11 gly1961glu exon 42 1bp del(T) Co 36 which creates stop at Co 38 Compound heterozygous 12 gly1961glu exon 42 IVS38-10 TϾC Compound heterozygous 13 gly1961glu exon 42 Heterozygous 14 gly1961glu exon 42 pro1380leu Compound heterozygous 15 gly1961glu exon 42 pro1380leu Compound heterozygous 16 gly1961glu exon 42 gly1961glu exon 42 Homozygous initial visit in the right eye was 0.87 (range, 0.10-1.40), whereas the median logMAR VA at the most recent FU visit was 1.00 (range, 0.18-2.80; P ϭ 0.325). Login to comment

[hide] Frequency of ABCA4 mutations in 278 Spanish contro... Br J Ophthalmol. 2009 Oct;93(10):1359-64. Epub 2008 Oct 31. Riveiro-Alvarez R, Aguirre-Lamban J, Lopez-Martinez MA, Trujillo-Tiebas MJ, Cantalapiedra D, Vallespin E, Avila-Fernandez A, Ramos C, Ayuso C
Frequency of ABCA4 mutations in 278 Spanish controls: an insight into the prevalence of autosomal recessive Stargardt disease.
Br J Ophthalmol. 2009 Oct;93(10):1359-64. Epub 2008 Oct 31., [PMID:18977788]

Abstract [show]
AIM: To determine the carrier frequency of ABCA4 mutations in order to achieve an insight into the prevalence of autosomal recessive Stargardt disease (arSTGD) in the Spanish population. METHODS: arSTGD patients (n = 133) were analysed using ABCR400 microarray and sequencing. Control subjects were analysed by two different strategies: 200 individuals were screened for the p.Arg1129Leu mutation by denaturing-HPLC and sequencing; 78 individuals were tested for variants with the microarray and sequencing. RESULTS: For the first strategy in control subjects, the p.Arg1129Leu variant was found in two heterozygous individuals, which would mean a carrier frequency for any variant of approximately 6.0% and a calculated arSTGD prevalence of 1:1000. For the second strategy, carrier frequency was 6.4% and therefore an estimated prevalence of the disease of 1:870. CONCLUSION: Calculated prevalence of arSTGD based on the ABCA4 carrier frequency could be considerably higher than previous estimation. This discrepancy between observed (genotypic) and estimated (phenotypic) prevalence could be due to the existence of non-pathological or low penetrance alleles, which may result in late-onset arSTGD or may be implicated in age-related macular degeneration. This situation should be regarded with special care when genetic counselling is given and further follow-up of these patients should be recommended.

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96 These Table 1 ABCA4 sequence variants identified in Spanish control population Mutant alleles Nucleotide change Amino acid change Number of cases Number of alleles Frequency (%) Homozygous individuals Mutations* c.661G.A p.Gly221Arg 1 1 0.64 None c.1140T.A p.Asn380Lys 1 1 0.64 None c.2588G.C p.Gly863Ala 1 1 0.64 None c.3113C.T p.Ala1038Val 1 1 0.64 None c.3899G.A p.Arg1300Gln 1 1 0.64 None c.5882G.A p.Gly1961Glu 1 1 0.64 None c.5908C.T p.Leu1970Phe 1 1 0.64 None c.6148G.C p.Val2050Leu 1 1 0.64 None c.6529G.A p.Asp2177Asn 2 2 1.28 None Total 10 Polymorphisms{ c.466A.G p.Ile156Val 5 5 3.2 None c.635G.A p.Arg212His 5 6 3.84 1 c.1268A.G p.His423Arg 43 48 30.7 5 c.1269C.T p.His423His 2 2 1.28 None IVS10+5delG 34 36 23 2 c.2828G.A p.Arg943Gln 1 1 0.64 None c.4203C.A p.Pro1401Pro 3 3 1.9 None IVS33+48C.T 59 75 48 16 c.5603A.T p.Asn1868Ile 4 4 2.5 None c.5682G.C p.Leu1894Leu 29 35 22.4 6 c.5814A.G p.Leu1938Leu 27 33 21.1 6 c.5843 C.T p.Pro1948Leu 9 10 6.4 1 c.5844A.G p.Pro1948Pro 27 32 20.5 5 c.6069C.T p.Ile2023Ile 11 12 7.7 1 c.6249C.T p.Ile2083Ile 12 14 8.9 2 c.6285T.C p.Asp2095Asp 24 26 16.6 2 c.6764G.T p.Ser2255Ile 12 13 8.3 1 *A total of 15 mutant alleles were detected. Login to comment
97 These Table 1 ABCA4 sequence variants identified in Spanish control population Mutant alleles Nucleotide change Amino acid change Number of cases Number of alleles Frequency (%) Homozygous individuals Mutations* c.661G.A p.Gly221Arg 1 1 0.64 None c.1140T.A p.Asn380Lys 1 1 0.64 None c.2588G.C p.Gly863Ala 1 1 0.64 None c.3113C.T p.Ala1038Val 1 1 0.64 None c.3899G.A p.Arg1300Gln 1 1 0.64 None c.5882G.A p.Gly1961Glu 1 1 0.64 None c.5908C.T p.Leu1970Phe 1 1 0.64 None c.6148G.C p.Val2050Leu 1 1 0.64 None c.6529G.A p.Asp2177Asn 2 2 1.28 None Total 10 Polymorphisms{ c.466A.G p.Ile156Val 5 5 3.2 None c.635G.A p.Arg212His 5 6 3.84 1 c.1268A.G p.His423Arg 43 48 30.7 5 c.1269C.T p.His423His 2 2 1.28 None IVS10+5delG 34 36 23 2 c.2828G.A p.Arg943Gln 1 1 0.64 None c.4203C.A p.Pro1401Pro 3 3 1.9 None IVS33+48C.T 59 75 48 16 c.5603A.T p.Asn1868Ile 4 4 2.5 None c.5682G.C p.Leu1894Leu 29 35 22.4 6 c.5814A.G p.Leu1938Leu 27 33 21.1 6 c.5843 C.T p.Pro1948Leu 9 10 6.4 1 c.5844A.G p.Pro1948Pro 27 32 20.5 5 c.6069C.T p.Ile2023Ile 11 12 7.7 1 c.6249C.T p.Ile2083Ile 12 14 8.9 2 c.6285T.C p.Asp2095Asp 24 26 16.6 2 c.6764G.T p.Ser2255Ile 12 13 8.3 1 *A total of 15 mutant alleles were detected. Login to comment

[hide] Peripapillary retinal nerve fiber layer thinning i... Am J Ophthalmol. 2009 Aug;148(2):260-265.e1. Epub 2009 May 5. Pasadhika S, Fishman GA, Allikmets R, Stone EM
Peripapillary retinal nerve fiber layer thinning in patients with autosomal recessive cone-rod dystrophy.
Am J Ophthalmol. 2009 Aug;148(2):260-265.e1. Epub 2009 May 5., [PMID:19406377]

Abstract [show]
PURPOSE: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness using spectral-domain optical coherence tomography in patients with autosomal recessive cone-rod dystrophy (CRD). DESIGN: Cross-sectional study. METHODS: Eleven patients (22 eyes) with CRD were studied, including 4 patients with identified ABCA4 gene mutations. Peripapillary RNFL thickness was measured in 16 segments from 4 quadrants. The analyses were based on age and disc size-adjusted normative data. An abnormal thinning was considered when RNFL thickness measurements were less than the fifth percentile in at least 2 of 4 segments in a quadrant. Mean RNFL thickness was compared quantitatively with normative data obtained from 134 subjects. RESULTS: Eight patients (73%) had peripapillary RNFL thinning in at least 1 quadrant of at least 1 eye, including 3 of 4 patients with known ABCA4 gene mutations. Peripapillary RNFL thinning in the temporal quadrant was seen most commonly in 11 (79%) of 14 eyes with thinning in at least 1 quadrant. Significant thinning of the overall peripapillary RNFL was observed in CRD patients compared with controls (P = .0002). Subgroup analysis showed that 8 (89%) of 9 patients who were older than 40 years had thinning in at least 1 quadrant of at least 1 eye. CONCLUSIONS: Peripapillary RNFL thinning was observed commonly in our patients with autosomal recessive CRD. The results confirm that the inner retinal structures can be affected in outer retinal disease. Careful evaluation of the inner retina may be important in determining the success rate of potential treatments for predominantly outer retinal diseases.

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60 Age (years) Gender Race Genetic Testing Results for the ABCA4 Gene Visual Acuity Fundus Findings Right Eye Left Eye Macula Pigmentation 1 60 Female White IVS40ϩ5 G¡A & cys54tyr exon 3, heterozygous 20/400 20/400 Pigment clumping Posterior pole, midperiphery 2 59 Female White glu328stop exon 8 & val767asp, heterozygous 3/200 3/400 Pigment clumping Posterior pole, midperiphery 3 44 Male White ala1038val exon 21 & leu541pro exon 12, heterozygousa 5/400 5/200 Pigment clumping Periphery 4 54 Female Black val989ala exon 20, heterozygous 20/400 CF Pigment clumping Posterior pole, peripapillary 5 42 Male Palestinian None detectedb 20/50 20/400 Drusen-like lesions, hypopigmentation - 6 45 Female Palestinian None detectedb 20/70 20/200 Drusen-like lesions, hypopigmentation - 7 63 Female Black None detectedb 20/200 20/200 Geographic atrophic lesions - 8 69 Female White No genetic testing 2/400 2/700 Pigment granularity - 9 62 Female White Pending 20/200 20/400 Bull`s-eye-like lesions - 10 16 Male White No genetic testing 10/300 10/200 Geographic atrophic lesions - 11 11 Male White No genetic testing 10/120 10/160 Bull`s-eye-like lesions and pigment granularity Few at midperiphery CF ϭ counting fingers. Login to comment
62 Age (years) Gender Race Genetic Testing Results for the ABCA4 Gene Visual Acuity Fundus Findings Right Eye Left Eye Macula Pigmentation 1 60 Female White IVS40af9;5 G&#a1;A & cys54tyr exon 3, heterozygous 20/400 20/400 Pigment clumping Posterior pole, midperiphery 2 59 Female White glu328stop exon 8 & val767asp, heterozygous 3/200 3/400 Pigment clumping Posterior pole, midperiphery 3 44 Male White ala1038val exon 21 & leu541pro exon 12, heterozygousa 5/400 5/200 Pigment clumping Periphery 4 54 Female Black val989ala exon 20, heterozygous 20/400 CF Pigment clumping Posterior pole, peripapillary 5 42 Male Palestinian None detectedb 20/50 20/400 Drusen-like lesions, hypopigmentation - 6 45 Female Palestinian None detectedb 20/70 20/200 Drusen-like lesions, hypopigmentation - 7 63 Female Black None detectedb 20/200 20/200 Geographic atrophic lesions - 8 69 Female White No genetic testing 2/400 2/700 Pigment granularity - 9 62 Female White Pending 20/200 20/400 Bull`s-eye-like lesions - 10 16 Male White No genetic testing 10/300 10/200 Geographic atrophic lesions - 11 11 Male White No genetic testing 10/120 10/160 Bull`s-eye-like lesions and pigment granularity Few at midperiphery CF afd; counting fingers. Login to comment

[hide] A comparison of fundus autofluorescence and retina... Invest Ophthalmol Vis Sci. 2009 Aug;50(8):3953-9. Epub 2009 Mar 25. Gomes NL, Greenstein VC, Carlson JN, Tsang SH, Smith RT, Carr RE, Hood DC, Chang S
A comparison of fundus autofluorescence and retinal structure in patients with Stargardt disease.
Invest Ophthalmol Vis Sci. 2009 Aug;50(8):3953-9. Epub 2009 Mar 25., [PMID:19324865]

Abstract [show]
PURPOSE: To improve the understanding of Stargardt disease by comparing structural changes seen on spectral domain optical coherence tomography (SD-OCT) to those visible on fundus autofluorescence (FAF). METHODS: FAF and SD-OCT were performed on 22 eyes of 11 patients with Stargardt disease. SD-OCT images were obtained at the fovea and at the eccentric preferred retinal locus (PRL). The diameters of absent (hypoautofluorescence) and abnormal FAF areas were measured. The extent of the transverse defect of the junction between the inner and outer segments of the photoreceptors (IS-OS) was measured in the foveal area. The PRL was evaluated with fundus photography and microperimetry. RESULTS: Twenty-one of 22 eyes showed defective FAF. In 17 eyes, FAF was absent in the fovea and in four eyes, FAF was abnormal. All eyes showed disorganization and/or loss of the IS-OS junction in the foveal area on SD-OCT. The diameter of the absent FAF area was smaller than the measurement of the IS-OS junction loss; the latter was closer to the diameter of the abnormal FAF area. Seventeen eyes had an eccentric PRL associated with a retinal area with no defects on FAF. CONCLUSIONS: In the majority of eyes, changes shown by SD-OCT correlated well with changes in FAF. However, in three patients, photoreceptor abnormalities were seen in the fovea on SD-OCT without an equivalent abnormality on FAF. This result suggests that in these patients, the structural integrity of the photoreceptors may be affected earlier than changes in the RPE at least as detected by FAF.

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97 Summary of Genetic and Selected Clinical Findings Patient Age Sex Allele 1 Allele 2 Visual Acuity (LogMAR) PRL (Degrees) PRL Location OD OS OD OS OD OS 1 12 M K346T ND 0.7 0.7 5.8 5.9 S S 2 42 M ND ND 1.0 1.0 1.9 2.0 S S 3 31 M G1961E G1961E 0.5 0.5 2.8 1.9 S S 4 56 M P1380L S1696N 0.7 0.7 8.4 8.0 S S 5 23 F L541P/A1038V G1961E 1.0 1.0 0.0 0.0 F F 6 62 F D1532N G1961E 1.3 0.4 3.0 0.0 T F 7 65 F G1961E ND 0.3 1.3 4.0 2.0 S S 8 30 F G1961E ND 0.4 0.4 2.9 3.0 S S 9 24 F P1380L P1380L 0.3 0.3 8.6 8.5 S S 10 15 F L541P/A1038V G1961E 0.0 0.0 0.0 0.0 F F 11 20 F L541P/A1038V ND 0.3 0.4 1.8 2.0 S S ND, not determined; S, superior; F, foveal; T, temporal. Login to comment

[hide] The role of the photoreceptor ABC transporter ABCA... Biochim Biophys Acta. 2009 Jul;1791(7):573-83. Epub 2009 Feb 20. Molday RS, Zhong M, Quazi F
The role of the photoreceptor ABC transporter ABCA4 in lipid transport and Stargardt macular degeneration.
Biochim Biophys Acta. 2009 Jul;1791(7):573-83. Epub 2009 Feb 20., [PMID:19230850]

Abstract [show]
ABCA4 is a member of the ABCA subfamily of ATP binding cassette (ABC) transporters that is expressed in rod and cone photoreceptors of the vertebrate retina. ABCA4, also known as the Rim protein and ABCR, is a large 2,273 amino acid glycoprotein organized as two tandem halves, each containing a single membrane spanning segment followed sequentially by a large exocytoplasmic domain, a multispanning membrane domain and a nucleotide binding domain. Over 500 mutations in the gene encoding ABCA4 are associated with a spectrum of related autosomal recessive retinal degenerative diseases including Stargardt macular degeneration, cone-rod dystrophy and a subset of retinitis pigmentosa. Biochemical studies on the purified ABCA4 together with analysis of abca4 knockout mice and patients with Stargardt disease have implicated ABCA4 as a retinylidene-phosphatidylethanolamine transporter that facilitates the removal of potentially reactive retinal derivatives from photoreceptors following photoexcitation. Knowledge of the genetic and molecular basis for ABCA4 related retinal degenerative diseases is being used to develop rationale therapeutic treatments for this set of disorders.

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134 Disease mutations, which are substituted in Stargardt disease, are shown in red italics - NBD1 (N965S, T971N, A1038V, S1071V, E1087K, R1108C); NBD2 (G1961E, L1971R, G1977S, L2027F, R2038W, R2077W, R2106C, R2107H). Login to comment
225 A subset of missense mutations reside in NBD1 (N965S, T971N, A1038V, S1071V, E1087K, R1108C, R1129L) and NBD2 (G1961E, L1971R, G1977S, L2027F, R2038W, R2077W, R2106C, R2107H). Login to comment

[hide] G1961E mutant allele in the Stargardt disease gene... Exp Eye Res. 2009 Jun 15;89(1):16-24. Epub 2009 Feb 13. Cella W, Greenstein VC, Zernant-Rajang J, Smith TR, Barile G, Allikmets R, Tsang SH
G1961E mutant allele in the Stargardt disease gene ABCA4 causes bull's eye maculopathy.
Exp Eye Res. 2009 Jun 15;89(1):16-24. Epub 2009 Feb 13., [PMID:19217903]

Abstract [show]
The aim of this study was to characterize the pathological and functional consequences of the G1961E mutant allele in the Stargardt disease gene ABCA4. Data from 15 patients were retrospectively reviewed and all the patients had at least one G1961E mutation. Comprehensive ophthalmic examination, full-field and pattern electroretinograms, and fundus autofluorescence (FAF) imaging were performed on all patients. Microperimetry, spectral-domain optical coherence tomography (OCT), and fluorescein angiography were performed in selected cases. Genetic screening was performed using the ABCR400 micro-array that currently detects 496 distinct ABCA4 variants. All patients had normal full-field scotopic and photopic electroretinograms (ERGs) and abnormal pattern electroretinograms (PERGs) performed on both eyes, and all the fundi had bull's eye maculopathy without retinal flecks on FAF. On OCT, 1 patient had disorganization of photoreceptor outer segment, 2 had outer nuclear layer (ONL) thinning likely due to photoreceptor atrophy proximal to the foveal center, and 3 had additional retinal pigment epithelium (RPE) atrophy. On microperimetry, 6 patients had eccentric superior fixation and amongst this group, 5 had an absolute scotoma in the foveal area. DNA analysis revealed that 3 patients were homozygous G1961E/G1961E and the rest were compound heterozygotes for G1961E and other ABCA4 mutations. The G1961E allele in either homozygosity or heterozygosity is associated with anatomical and functional pathologies limited to the parafoveal region and a trend to delayed onset of symptoms, relative to other manifestations of ABCA4 mutations. Our observations support the hypothesis that the G1961E allele contributes to localized macular changes rather than generalized retinal dysfunction, and is a cause of bull's eye maculopathy in either the homozygosity or heterozygosity state. In addition, genetic testing provides precise diagnosis of the underlying maculopathy, and current non-invasive imaging techniques could be used to detect photoreceptor damage at the earliest clinical onset of the disease.

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89 Of the compound heterozygous group, 5 patients from 2 families had the complex mutation L541P/A1038V, 2 patients (siblings) had the splicing mutation IVS20 þ 5G / A, and 5 patients had missense mutations Q636H, R2077W, T1253M, C54Y and D1532N (Table 1). Login to comment
122 Five patients from 2 unrelated families carried the complex mutation L541P/A1038V in addition to the G1961E allele. Login to comment
142 Case #, sex Age of onset Duration (years) Visual acuity (OD, OS) Allele 2 Bull`s eye type (FAF) SD-OCT MP-1 1, f 20 1 20/25, 20/40 G1961E (homozygous) B Not tested Not tested 2, f 49 13 20/200, 20/150 G1961E (homozygous) B Photoreceptor loss, thinner ONL and RPE atrophy Absolute scotoma in the central 4 degrees OD and in the central 6 degrees OS, eccentric PRL (superior retina) 3, m 19 13 20/70, 20/70 G1961E (homozygous) A Not tested Absolute scotoma in the central 6 degrees in both eyes, eccentric PRL (superior retina) 4.1, f 17 30 20/200, 20/200 L541P/A1038V B Not tested Not tested 4.2, m 28 2 20/25, 20/30 L541P/A1038V B Not tested Decreased sensitivity by 6 dB in the central 2 degrees in both eyes, foveal fixation 4.3, m 28 2 20/30, 20/40 L541P/A1038V B Not tested Decreased sensitivity by 9 dB OD and 11 dB OS in the central 2 degrees, foveal fixation 5.1, f 14 5 20/200, 20/400 L541P/A1038V C Photoreceptor loss (foveal optical gap), thinner ONL and normal RPE Decreased sensitivity by 8 dB in the central 2 degrees in both eyes, eccentric PRL (superior retina) 5.2, f 14 1 20/20, 20/25 L541P/A1038V A Photoreceptor disorganization, normal ONL and normal RPE Decreased sensitivity by 6 dB in the central 2 degrees in both eyes, foveal fixation 6.1, f 17 5 20/100, 20/100 IVS20 þ 5G / A C Photoreceptor loss, thinner ONL and RPE atrophy Absolute scotoma in the central 2 degrees in both eyes, eccentric PRL (superior retina) 6.2, m 14 3 20/40, 20/25 IVS20 þ 5G / A A Photoreceptor loss (foveal optical gap), thinner ONL and normal RPE Absolute scotoma in the central 2 degrees OD and decreased sensitivity by 18 dB in the central 2 degrees OS, eccentric PRL (superior retina) 7, m 28 12 20/200, 20/150 Q636H B Photoreceptor loss, thinner ONL and RPE atrophy Not tested 8, f 25 9 20/80, 20/25 R2077W B Not tested Not tested 9, m 67 2 20/800, 20/60 T1253M B Not tested Not tested 10, f 26 10 20/80, 20/80 C54Y B Not tested Not tested 11, f 44 20 20/400, 20/60 D1532N C Not tested Absolute scotoma in the central 8-10 degrees OD and absolute scotoma in the central 8 degrees OS, eccentric PRL (superior retina) Abbreviations: m, male; f, female; OD, right eye; OS, left eye; FAF, fundus autofluorescence; bull`s eye type A, presence of a ring of increase autofluorescence surrounding decreased autofluorescence; bull`s eye type B, decreased fovea autofluorescence without a surrounding ring of increase autofluorescence; bull`s eye type C, speckled macular appearance with slightly increased surround autofluorescence; SD-OCT, spectral-domain optical coherence tomography; ONL, outer nuclear layer; MP-1, microperimetry; and PRL, preferred retinal location. Login to comment
164 In the compound heterozygous group, 5 patients had the complex mutation allele L541P/A1038V, in addition to G1961E. Login to comment
168 The L541P/A1038V mutation has been described in patients with more favorable clinical prognosis (Hargitai et al., 2005). Login to comment
169 Similarly, although G1961E is considered a ''mild- to-moderate`` allele, it has been reported in bull`s eye maculopathy with more severe phenotype such as extensive atrophic RPE changes (Gerth et al., 2002; Simonelli et al., 2005). Login to comment
143 Case #, sex Age of onset Duration (years) Visual acuity (OD, OS) Allele 2 Bull`s eye type (FAF) SD-OCT MP-1 1, f 20 1 20/25, 20/40 G1961E (homozygous) B Not tested Not tested 2, f 49 13 20/200, 20/150 G1961E (homozygous) B Photoreceptor loss, thinner ONL and RPE atrophy Absolute scotoma in the central 4 degrees OD and in the central 6 degrees OS, eccentric PRL (superior retina) 3, m 19 13 20/70, 20/70 G1961E (homozygous) A Not tested Absolute scotoma in the central 6 degrees in both eyes, eccentric PRL (superior retina) 4.1, f 17 30 20/200, 20/200 L541P/A1038V B Not tested Not tested 4.2, m 28 2 20/25, 20/30 L541P/A1038V B Not tested Decreased sensitivity by 6 dB in the central 2 degrees in both eyes, foveal fixation 4.3, m 28 2 20/30, 20/40 L541P/A1038V B Not tested Decreased sensitivity by 9 dB OD and 11 dB OS in the central 2 degrees, foveal fixation 5.1, f 14 5 20/200, 20/400 L541P/A1038V C Photoreceptor loss (foveal optical gap), thinner ONL and normal RPE Decreased sensitivity by 8 dB in the central 2 degrees in both eyes, eccentric PRL (superior retina) 5.2, f 14 1 20/20, 20/25 L541P/A1038V A Photoreceptor disorganization, normal ONL and normal RPE Decreased sensitivity by 6 dB in the central 2 degrees in both eyes, foveal fixation 6.1, f 17 5 20/100, 20/100 IVS20 &#fe; 5G / A C Photoreceptor loss, thinner ONL and RPE atrophy Absolute scotoma in the central 2 degrees in both eyes, eccentric PRL (superior retina) 6.2, m 14 3 20/40, 20/25 IVS20 &#fe; 5G / A A Photoreceptor loss (foveal optical gap), thinner ONL and normal RPE Absolute scotoma in the central 2 degrees OD and decreased sensitivity by 18 dB in the central 2 degrees OS, eccentric PRL (superior retina) 7, m 28 12 20/200, 20/150 Q636H B Photoreceptor loss, thinner ONL and RPE atrophy Not tested 8, f 25 9 20/80, 20/25 R2077W B Not tested Not tested 9, m 67 2 20/800, 20/60 T1253M B Not tested Not tested 10, f 26 10 20/80, 20/80 C54Y B Not tested Not tested 11, f 44 20 20/400, 20/60 D1532N C Not tested Absolute scotoma in the central 8-10 degrees OD and absolute scotoma in the central 8 degrees OS, eccentric PRL (superior retina) Abbreviations: m, male; f, female; OD, right eye; OS, left eye; FAF, fundus autofluorescence; bull`s eye type A, presence of a ring of increase autofluorescence surrounding decreased autofluorescence; bull`s eye type B, decreased fovea autofluorescence without a surrounding ring of increase autofluorescence; bull`s eye type C, speckled macular appearance with slightly increased surround autofluorescence; SD-OCT, spectral-domain optical coherence tomography; ONL, outer nuclear layer; MP-1, microperimetry; and PRL, preferred retinal location. Login to comment
165 In the compound heterozygous group, 5 patients had the complex mutation allele L541P/A1038V, in addition to G1961E. Login to comment

[hide] Lipofuscin- and melanin-related fundus autofluores... Am J Ophthalmol. 2009 May;147(5):895-902, 902.e1. Epub 2009 Feb 25. Kellner S, Kellner U, Weber BH, Fiebig B, Weinitz S, Ruether K
Lipofuscin- and melanin-related fundus autofluorescence in patients with ABCA4-associated retinal dystrophies.
Am J Ophthalmol. 2009 May;147(5):895-902, 902.e1. Epub 2009 Feb 25., [PMID:19243736]

Abstract [show]
PURPOSE: To compare melanin-related near-infrared fundus autofluorescence (NIA; excitation 787 nm, emission > 800 nm) to lipofuscin-related fundus autofluorescence (FAF; excitation 488 nm, emission > 500 nm) in patients with retinal dystrophies associated with ABCA4 gene mutations (ABCA4-RD). DESIGN: Observational case series. METHODS: Sixteen consecutive patients with ABCA4-RD diagnosed in one institution were included. FAF and NIA imaging were performed with a confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph 2; Heidelberg Engineering, Heidelberg, Germany). The pattern and size of retinal pigment epithelial (RPE) alterations detected with FAF and NIA were evaluated. RESULTS: FAF and NIA alterations were detected in all patients. In 7 of 16 patients, the alterations progressed beyond the vascular arcades, and in 9 of 16, they were confined to the macula. Spots of increased NIA (4/16) were less frequent compared with spots of increased FAF (15/16). Confluent patches of reduced NIA were frequent (12/16), and severely reduced NIA was observed in 3 cases. Areas with reduced NIA corresponded to either increased or reduced FAF. Preservation of subfoveal FAF or NIA corresponded to visual acuity > or = 0.4. Abnormalities detected with NIA were more extensive or more severe compared to FAF in 15 of 16 patients. CONCLUSION: Patterns of FAF and NIA indicate different involvement of lipofuscin and melanin and their derivates in the pathophysiologic process of ABCA4-RD. NIA imaging provides a noninvasive in vivo visualization of RPE abnormalities that may precede FAF alterations during the degenerative process. Combined FAF and NIA imaging will provide further insight in the development of ABCA4-RD and could help to monitor future therapeutic interventions.

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32 Age Gender ABCA4 Mutation VA RE/LE Full-field ERG Multifocal ERG Group 1a CRD 2808 34 F c.5413AϾG (p.Asn1805Asp) c.4880_4903dup24 (p.Leu1627_Ala1634dup) 0.05 0.05 DA and LA markedly reduced No recordable potentials CRD 2830 53 F c.2690CϾT (p.Thr897Ile), c.6176GϾC (p.Gly2059Ala) 0.5 0.7 DA and LA moderately reduced Pericentral amplitude reduction CRD 2797 54 M c.4297GϾA (p.Val1433Ile) 2. mutation not foundc 0.1 0.16 DA and LA moderately reduced Not done SD 2872 44 F c.4462TϾC (p.Cys1488Arg) 2. mutation not done 0.6 0.7 DA and LA borderline Central amplitude reduction CRD 2861 72 F c.122GϾA (p.Trp41Ter) 2. mutation not done 0.4 0.5 DA: mildly and LA: moderately reduced Central amplitude reduction CRD 2644 67 F c.634CϾT (p.Arg212Cys), c.656GϾC (p.Arg219Thr), c.2588GϾC (p.Gly863Ala/ delGly863) 0.6 0.04 DA and LA moderately reduced Central amplitude reduction CRD 2936 44 F c.1622TϾC (p.Leu541Pro)/ c.3113CϾT (p.Ala1038Val), 2. mutation not done 1.0 1.0 DA: mildly and LA: moderately reduced Pericentral amplitude reduction Group 2b SD 2837 42 M c.1622TϾC (p.Leu541Pro)/ c.3113CϾT (p.Ala1038Val), c.5882GϾA (p.Gly1961Glu) 0.16 0.16 Normal Central amplitude reduction SD 2780 37 M c.768GϾ;T (splice mutation) c.5882GϾA (p.Gly1961Glu) 0.1 0.1 Normal Central amplitude reduction SD 2942 47 F c.1622TϾC (p.Leu541Pro) c.6320 GϾA (p.Arg2107His) 0.1 0.16 Not done Central amplitude reduction SD 2930 40 F c.6089GϾA (p.Arg2030Gln) c.6543del36bp, (p.Leu2182_Phe2193del) 0.1 0.1 DA and LA mildly reduced Central amplitude reduction SD 2933 43 F c.1609CϾT (p.Arg537Cys) c.5882GϾA (p.Gly1961Glu) c.1654GϾA (p.Val552Ile) 0.05 0.1 Normal Not done SD 2669 13 F c.768GϾT (splice mutation) c.6449GϾA (p.Cys2150Tyr) 0.1 0.16 DA and LA borderline Central amplitude reduction SD 2700 22 F c.1609CϾT (p.Arg537Cys) c.2588GϾC (p.Gly863Ala) 0.1 0.1 Normal Central amplitude reduction SD 2833 29 M c.1928TϾG (p.Val643Gly) 2. mutation not foundc 0.1 0.1 Normal Not done SD 2799 13 M c.3113CϾT (p.Ala1038Val) c.5461-10TϾC 0.4 0.4 Not done Central amplitude reduction CRD ϭ cone-rod dystrophy; DA ϭ dark adaptation; ERG ϭ electroretinography; F ϭ female; LA ϭ light adaptation; LE ϭ left eye; M ϭ male; RE ϭ right eye; SD ϭ Stargardt disease; VA ϭ visual acuity. Login to comment

[hide] ABCA4 disease progression and a proposed strategy ... Hum Mol Genet. 2009 Mar 1;18(5):931-41. Epub 2008 Dec 12. Cideciyan AV, Swider M, Aleman TS, Tsybovsky Y, Schwartz SB, Windsor EA, Roman AJ, Sumaroka A, Steinberg JD, Jacobson SG, Stone EM, Palczewski K
ABCA4 disease progression and a proposed strategy for gene therapy.
Hum Mol Genet. 2009 Mar 1;18(5):931-41. Epub 2008 Dec 12., [PMID:19074458]

Abstract [show]
Autosomal recessive retinal diseases caused by mutations in the ABCA4 gene are being considered for gene replacement therapy. All individuals with ABCA4-disease show macular degeneration, but only some are thought to progress to retina-wide blindness. It is currently not predictable if or when specific ABCA4 genotypes will show extramacular disease, and how fast it will progress thereafter. Early clinical trials of focal subretinal gene therapy will aim to arrest disease progression in the extramacular retina. In 66 individuals with known disease-causing ABCA4 alleles, we defined retina-wide disease expression by measuring rod- and cone-photoreceptor-mediated vision. Serial measurements over a mean period of 8.7 years were consistent with a model wherein a normal plateau phase of variable length was followed by initiation of retina-wide disease that progressed exponentially. Once initiated, the mean rate of disease progression was 1.1 log/decade for rods and 0.45 log/decade for cones. Spatio-temporal progression of disease could be described as the sum of two components, one with a central-to-peripheral gradient and the other with a uniform retina-wide pattern. Estimates of the age of disease initiation were used as a severity metric and contributions made by each ABCA4 allele were predicted. One-third of the non-truncating alleles were found to cause more severe disease than premature truncations supporting the existence of a pathogenic component beyond simple loss of function. Genotype-based inclusion/exclusion criteria and prediction of the age of retina-wide disease initiation will be invaluable for selecting appropriate candidates for clinical trials in ABCA4 disease.

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47 At age 11, P36 (A1038V;L541P/ N965S) had a sensitivity loss of 5.3 dB which was within normal limits; 8 years later at age 19 there was no significant change in sensitivity loss (5.6 dB). Login to comment
127 And for an additional eight mutations (G818E, A1038V;L541P, E1087D, R1108C, E1122K, IVS40þ5G.A, L1940P and K2172R), we performed severity estimates recursively by using estimates established above. Login to comment
151 Estimated severity of ABCA4 alleles and their properties ABCA4 allele Delay of retina-wide disease initiation (years)a In vitro or in vivo studiesb Molecular structural localizationc C2150Y 225.8 NBD-2 A1038V;L541P 214.0 35, 38 ECD-1/NBD-1 IVS38-10 T.C 211.1 L244P 25.7 ECD-1 E1122K 23.5 NBD-1 C54Y 22.1 35 ECD-1 IVS35þ2 T.C 22.1 R602W 21.8 38 ECD-1 V1896D 21.8 TM12 L1940P 21.4 NBD-2 Truncation mutationsd 0.0 E1087D 2.8 NBD-1 R220C 3.9 ECD-1 A1598D 3.9 ECD-2 R1640Q 3.9 ECD-2 R1098C 4.9 NBD-1 P1380L 7.4 35 TM7 N965S 7.6 35 NBD-1 V1433I 8.6 ECD-2 R1108C 10.4 35 NBD-1 T1526M 14.5 35 ECD-2 R2030Q 14.5 NBD-2 L2027F 15.1 35,37 NBD-2 G818E 17.3 35 TM5/TM6 S100P 18.2 ECD-1 L1201R 18.2 NBD-1 R18W 18.5 Nt D600E 18.5 ECD-1 L11P 21.7 Nt D654N 25.3 36 ECD-1 K2172R 27.9 NBD-2 IVS40þ5 G.A 28.1 G1961E 37.9 35 NBD-2 G1961R 44.0 NBD-2 a Delay of retina-wide disease initiation relative to the standard of age 10.6 years. Login to comment

[hide] ABCA4 mutations in Portuguese Stargardt patients: ... Mol Vis. 2009;15:584-91. Epub 2009 Mar 25. Maia-Lopes S, Aguirre-Lamban J, Castelo-Branco M, Riveiro-Alvarez R, Ayuso C, Silva ED
ABCA4 mutations in Portuguese Stargardt patients: identification of new mutations and their phenotypic analysis.
Mol Vis. 2009;15:584-91. Epub 2009 Mar 25., [PMID:19365591]

Abstract [show]
PURPOSE: To resolve the spectrum of causative retina-specific ATP-binding cassette transporter gene (ABCA4) gene mutations in Portuguese Stargardt (STGD) patients and compare allele frequencies obtained in this cohort with those of previous population surveys. METHODS: Using a microarray technique (ABCR400 gene chip), we screened all previously reported ABCA4 gene mutations in the genomic DNA of 27 patients from 21 unrelated Stargardt families whose phenotypes had been clinically evaluated using psychophysics and electrophysiological measurements. Furthermore, we performed denaturing high performance liquid chromatography whenever one or both mutant alleles failed to be detected using the ABCR gene chip. RESULTS: A total of 36 mutant alleles (out of the 54 tested) were identified in STGD patients, resulting in a detection rate of 67%. Two mutant alleles were present in 12 out of 21 STGD families (57%), whereas in four out of 21 (19%) of the families, only one mutant allele was found. We report the presence of 22 putative pathogenic alterations, including two sequence changes not found in other populations, c.2T>C (p.Met1Thr) and c.4036_4037delAC (p.Thr1346fs), and two novel disease-associated variants, c.400C>T (p.Gln134X) and c.4720G>T (p.Glu1574X). The great majority of the mutations were missense (72.7%). Seven frameshift variants (19.4%), three nonsense mutations (8.3%), and one splicing sequence change (2.7%) were also found in STGD chromosomes. The most prevalent pathologic variant was the missense mutation p.Leu11Pro. Present in 19% of the families, this mutation represents a quite high prevalence in comparison to other European populations. In addition, 23 polymorphisms were also identified, including four novel intronic sequence variants. CONCLUSIONS: To our knowledge, this study represents the first report of ABCA4 mutations in Portuguese STGD patients and provides further evidence of different mutation frequency across populations. Phenotypic characterization of novel putative mutations was addressed.

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69 4139C>T(28) p.Asn96Asp [30]/p.Pro1380Leu [13] 2 4458 Mi 5 8/10 / 6/10 ND / ND ND/ND 4455 S 8 1/10 / 8/10 ND / ND ND/ND 3 4431 Mo 6 1,6/10 / 1,6/10 c.1804C>T(13) / c.IVS+5G>A(40) p.Arg602Trp [30]/SPLICE [11] 4 4626 S 6 FC / FC c.3211_3212insGT(22) / c.3211_3212insGT(22) p.Asp1048fs [5]/p.Asp1048fs [5] 5 4514 S 12 1/10 / 1/10 c.32T>C(1) / c. Login to comment
70 [1A>G(1)]+[6089G>A(44)] p.Leu11Pro [12]/p.(Met1Val [6])+(Arg2030Gln [9]) 6 4525 Mo 14 1/10 / 1/10 ND / c.868C>T(8) ND/p.Arg290Trp [6] 7 4585 Mo 11 0.5/10 / 0.5/10 c.6079C>T(44) / ND p.Leu2027Phe [5]/ND 8 4678 Mo 9 0.5/10 / 1/10 c.3113C>T(21) / c.3602T>G(24) p.Ala1038Val [5]/p.Leu1201Arg [9] 9 4675 Mo 7 0.5/10 / 1/10 c.2T<C(1) / c.2T<C(1) p.Met1Thr/p.Met1Thr 10 4737 Mo 24 1.2/10 / 1.2/10 c.5882G>A(42) / c.3211_3212insGT(22) p.Gly1961Glu [4]/p.Asp1048fs 11 4613 S 9 FC / FC c. Login to comment

[hide] ABCA4 gene analysis in patients with autosomal rec... Eur J Hum Genet. 2008 Jul;16(7):812-9. Epub 2008 Feb 20. Kitiratschky VB, Grau T, Bernd A, Zrenner E, Jagle H, Renner AB, Kellner U, Rudolph G, Jacobson SG, Cideciyan AV, Schaich S, Kohl S, Wissinger B
ABCA4 gene analysis in patients with autosomal recessive cone and cone rod dystrophies.
Eur J Hum Genet. 2008 Jul;16(7):812-9. Epub 2008 Feb 20., [PMID:18285826]

Abstract [show]
The ATP-binding cassette (ABC) transporters constitute a family of large membrane proteins, which transport a variety of substrates across membranes. The ABCA4 protein is expressed in photoreceptors and possibly functions as a transporter for N-retinylidene-phosphatidylethanolamine (N-retinylidene-PE), the Schiff base adduct of all-trans-retinal with PE. Mutations in the ABCA4 gene have been initially associated with autosomal recessive Stargardt disease. Subsequent studies have shown that mutations in ABCA4 can also cause a variety of other retinal dystrophies including cone rod dystrophy and retinitis pigmentosa. To determine the prevalence and mutation spectrum of ABCA4 gene mutations in non-Stargardt phenotypes, we have screened 64 unrelated patients with autosomal recessive cone (arCD) and cone rod dystrophy (arCRD) applying the Asper Ophthalmics ABCR400 microarray followed by DNA sequencing of all coding exons of the ABCA4 gene in subjects with single heterozygous mutations. Disease-associated ABCA4 alleles were identified in 20 of 64 patients with arCD or arCRD. In four of 64 patients (6%) only one mutant ABCA4 allele was detected and in 16 patients (25%), mutations on both ABCA4 alleles were identified. Based on these data we estimate a prevalence of 31% for ABCA4 mutations in arCD and arCRD, supporting the concept that the ABCA4 gene is a major locus for various types of degenerative retinal diseases with abnormalities in cone or both cone and rod function.

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70 of alleles Reference Missense: 6 c.731T4Ca p.L244P 2 23 12 c.1622T4Cb p.L541P 1 5 13 c.1928T4G p.V643G 1 9 17 c.2588G4C p.G863A and p.G863del 2 4 21 c.3113C4Tb p.A1038V 1 4 25 c.3608G4A p.G1203E 1 24 28 c.4139C4T p.P1380L 2 25 30 c.4457C4T p.P1486L 1 25 30 c.4462T4C p.C1488R 1 25 37 c.5285C4A p.A1762D 1 24 41 c.5819T4C p.L1940P 1 26 42 c.5882G4A p.G1961E 1 9 45 c.6148G4C p.V2050L 1 25 45 c.6229C4T p.R2077W 1 25 Nonsense: 6 c.700C4T p.Q234X 1 This study 6 c.735T4G p.Y245X 2 24 28 c.4234C4T p.Q1412X 1 10 Deletion: 24 c.3539_3554del p.S1181PfsX8 1 This study 43 c.5917delG p.V1973X 3 27 Splice site/intronic: 26 c.5196+1G4A Splicing 1 9 34 c.4848+2T4C Splicing 1 This study 36 c.5196+1_5196+4del Splicing 1 15 39 c.5461À10T4C Unknown 8 14 40 c.5714+5G4A Splicing? Login to comment

[hide] Stargardt's disease and the ABCR gene. Semin Ophthalmol. 2008 Jan-Feb;23(1):59-65. Westerfeld C, Mukai S
Stargardt's disease and the ABCR gene.
Semin Ophthalmol. 2008 Jan-Feb;23(1):59-65., [PMID:18214793]

Abstract [show]
Stargardt's disease is an autosomal recessive form of juvenile macular degeneration. The clinical presentation, relevant ancillary tests, and classic histologic features will be reviewed. The role of genetic mutations in the pathophysiology of Stargardt's disease will also be explored. Stargardt's disease is caused by mutations in the ABCR (ABCA4) gene on chromosome 1. Mutations in this gene have also been attributed to some cases of cone-rod dystrophy, retinitis pigmentosa, and age-related macular degeneration. The genetic and molecular pathways that produce Stargardt's disease will be discussed. Future diagnostic and therapeutic objectives for this visually disabling condition will also be presented.

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94 Certain mutant alleles causing Stargardt`s such as G863A, A1038V, and G1961E appear to be more common and may have altered frequencies in different populations, presumably because of founder effect (Maugeri et al., 1999; Simonelli et al., 2000). Login to comment

[hide] Quantifying fixation in patients with Stargardt di... Vision Res. 2007 Jul;47(15):2076-85. Epub 2007 Jun 11. Reinhard J, Messias A, Dietz K, Mackeben M, Lakmann R, Scholl HP, Apfelstedt-Sylla E, Weber BH, Seeliger MW, Zrenner E, Trauzettel-Klosinski S
Quantifying fixation in patients with Stargardt disease.
Vision Res. 2007 Jul;47(15):2076-85. Epub 2007 Jun 11., [PMID:17562343]

Abstract [show]
Fixational eye movements in 60 eyes of 30 patients with ABCA4-associated Stargardt disease were recorded by a Scanning Laser Ophthalmoscope (SLO). The results were quantified by two new fixation quality measures expressing the eccentricity of the preferred retinal locus (PRL) non-parametrically, and fixation stability by a dynamic index. 46 eyes (77%) fixated eccentrically; in 32 eyes (70% of the eccentrically fixating eyes) the PRL was located above the central retinal lesion. PRL eccentricity correlated positively with logMAR visual acuity (r=.72; p<.0001) and negatively with fixation stability (r=-.58; p<.0001). Multiple PRL were found only in three eyes.

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186 of PRL ABCA4 allel1 exon mut 1 ABCA4 allel2 exon mut 2 1 m 32 OD 2 0.4 0.0 90.0 211.0 1 48 L2241V n.f. OS 2 0.6 0.0 90.0 181.6 1 2 f 55 OD 29 0.1 9.7 60.3 9874.6 1 - - - - OS 29 0.1 6.8 67.5 68260.1 2 3 f 38 OD 16 0.05 6.4 73.7 4962.8 1 14 W663X 42 G1961E OS 7 0.4 0.0 90.9 143.5 1 4 m 23 OD 7 0.1 5.7 81.8 664.3 1 40 R1898H 43 G1975R OS 6 0.1 7.0 80.6 594.2 1 5 m 16 OD 7 0.05 7.4 81.0 1052.0 1 12+21 L541P+ 40 IVS40+5 OS 7 0.05 5.0 73.3 11500.0 1 A1038V G->A 6 m 34 OD 34 0.1 0.0 76.2 924.2 1 n.f. n.f. OS 34 0.1 0.0 74.3 1106.2 1 7 m 17 OD 11 0.1 3.1 79.1 3517.6 1 - - - - OS 11 0.1 3.6 70.0 2226.1 1 8 m 46 OD 14 0.5 3.6 80.6 3986.2 1 11 E471K 42 G1961E OS 14 0.2 3.7 58.3 40731.5 1 9 f 26 OD 15 0.1 6.0 70.5 3215.2 1 17 G863A n.f. OS 15 0.1 8.5 56.5 14734.9 1 10 f 19 OD 2 0.1 7.9 65.7 3260.0 1 3 P68L 36 S1689P OS 2 0.1 7.0 63.9 2964.8 1 11 f 34 OD 30 0.4 0.0 88.2 234.1 1 28 E1399K 42 G1961E OS 30 0.4 0.0 87.9 350.0 1 12 m 59 OD 5 0.1 5.2 79.2 1715.5 1 42 G1961E n.f. OS 5 0.1 4.4 75.0 3839.5 1 13 m 35 OD 20 0.05 9.7 72.9 8164.8 1 17 G863A 37 Q1750X OS 20 0.05 10.3 64.9 9820.4 1 14 m 43 OD 29 HM 16.0 58.5 18228.0 1 17 G863A 37 Q1750X OS 29 HM 15.6 42.1 14173.5 1 15 f 32 OD 10 0.05 6.5 61.3 10195.5 1 21 A1038V n.f. OS 10 0.05 5.0 56.7 7560.7 1 16 m 46 OD 4 0.05 8.5 51.1 8641.6 1 12+21 L541P+ 17 G863A OS 4 0.3 5.0 51.1 19827.1 1 A1038V 17 m 43 OD 3 0.5 0.0 90.7 190.9 1 - - - - OS 3 0.7 0.0 81.9 402.2 1 18 f 31 OD 27 1/15 9.8 69.3 2268.5 1 22 R1108C n.f. OS 27 0.1 17.2 60.9 4237.0 1 19 f 23 OD 5 0.05 6.0 72.9 3751.2 1 28 E1399K 43 G1977S OS 5 0.05 6.2 74.8 3578.9 1 20 f 16 OD 5 0.1 6.0 75.8 708.0 1 22 R1108C n.f. OS 5 0.1 5.4 82.4 449.6 1 21 m 38 OD 23 0.1 8.2 53.7 53733.8 2 - - - - OS 12 0.1 6.2 60.3 80873.8 2 22 m 40 OD 6 0.05 16.6 60.8 11677.8 1 14 R681X n.f. OS 6 0.1 10.0 60.6 5134.5 1 23 f 24 OD 3 0.1 6.7 90.5 577.8 1 6 G768T/ n.f. OS 3 0.1 7.1 83.6 3015.2 1 splice 24 m 13 OD 3 0.05 6.9 65.2 1882.7 1 - - - - OS 3 0.05 7.3 53.7 3844.3 1 25 f 39 OD 34 HM 7.0 54.3 24440.2 1 n.f. n.f. OS 34 1/60 10.6 77.6 1245.6 1 26 f 27 OD 2 0.2 0.0 91.8 127.4 1 17 G863A 28 Q1412X OS 2 0.6 0.0 94.9 69.2 1 27 m 25 OD 1 0.3 0.0 70.7 5670.4 1 n.f. n.f. OS 1 0.4 0.0 75.6 764.9 1 28 m 17 OD 3 0.2 0.8 67.3 4244.1 1 - - - - OS 3 0.3 0.0 80.6 2429.2 1 29 m 28 OD 2,5 0.1 5.4 80.8 795.0 1 - - - - OS 2,5 0.1 4.2 64.3 2101.1 1 30 f 27 OD 20 0.1 6.7 88.2 183.6 1 G1961E G1961E OS 20 0.1 10.9 81.0 448.2 1 Dis. dur., disease duration (years); HM, recognition of hand movements; VA, visual acuity in European decimals. Login to comment
183 of PRL ABCA4 allel1 exon mut 1 ABCA4 allel2 exon mut 2 1 m 32 OD 2 0.4 0.0 90.0 211.0 1 48 L2241V n.f. OS 2 0.6 0.0 90.0 181.6 1 2 f 55 OD 29 0.1 9.7 60.3 9874.6 1 - - - - OS 29 0.1 6.8 67.5 68260.1 2 3 f 38 OD 16 0.05 6.4 73.7 4962.8 1 14 W663X 42 G1961E OS 7 0.4 0.0 90.9 143.5 1 4 m 23 OD 7 0.1 5.7 81.8 664.3 1 40 R1898H 43 G1975R OS 6 0.1 7.0 80.6 594.2 1 5 m 16 OD 7 0.05 7.4 81.0 1052.0 1 12+21 L541P+ 40 IVS40+5 OS 7 0.05 5.0 73.3 11500.0 1 A1038V G->A 6 m 34 OD 34 0.1 0.0 76.2 924.2 1 n.f. n.f. OS 34 0.1 0.0 74.3 1106.2 1 7 m 17 OD 11 0.1 3.1 79.1 3517.6 1 - - - - OS 11 0.1 3.6 70.0 2226.1 1 8 m 46 OD 14 0.5 3.6 80.6 3986.2 1 11 E471K 42 G1961E OS 14 0.2 3.7 58.3 40731.5 1 9 f 26 OD 15 0.1 6.0 70.5 3215.2 1 17 G863A n.f. OS 15 0.1 8.5 56.5 14734.9 1 10 f 19 OD 2 0.1 7.9 65.7 3260.0 1 3 P68L 36 S1689P OS 2 0.1 7.0 63.9 2964.8 1 11 f 34 OD 30 0.4 0.0 88.2 234.1 1 28 E1399K 42 G1961E OS 30 0.4 0.0 87.9 350.0 1 12 m 59 OD 5 0.1 5.2 79.2 1715.5 1 42 G1961E n.f. OS 5 0.1 4.4 75.0 3839.5 1 13 m 35 OD 20 0.05 9.7 72.9 8164.8 1 17 G863A 37 Q1750X OS 20 0.05 10.3 64.9 9820.4 1 14 m 43 OD 29 HM 16.0 58.5 18228.0 1 17 G863A 37 Q1750X OS 29 HM 15.6 42.1 14173.5 1 15 f 32 OD 10 0.05 6.5 61.3 10195.5 1 21 A1038V n.f. OS 10 0.05 5.0 56.7 7560.7 1 16 m 46 OD 4 0.05 8.5 51.1 8641.6 1 12+21 L541P+ 17 G863A OS 4 0.3 5.0 51.1 19827.1 1 A1038V 17 m 43 OD 3 0.5 0.0 90.7 190.9 1 - - - - OS 3 0.7 0.0 81.9 402.2 1 18 f 31 OD 27 1/15 9.8 69.3 2268.5 1 22 R1108C n.f. OS 27 0.1 17.2 60.9 4237.0 1 19 f 23 OD 5 0.05 6.0 72.9 3751.2 1 28 E1399K 43 G1977S OS 5 0.05 6.2 74.8 3578.9 1 20 f 16 OD 5 0.1 6.0 75.8 708.0 1 22 R1108C n.f. OS 5 0.1 5.4 82.4 449.6 1 21 m 38 OD 23 0.1 8.2 53.7 53733.8 2 - - - - OS 12 0.1 6.2 60.3 80873.8 2 22 m 40 OD 6 0.05 16.6 60.8 11677.8 1 14 R681X n.f. OS 6 0.1 10.0 60.6 5134.5 1 23 f 24 OD 3 0.1 6.7 90.5 577.8 1 6 G768T/ n.f. OS 3 0.1 7.1 83.6 3015.2 1 splice 24 m 13 OD 3 0.05 6.9 65.2 1882.7 1 - - - - OS 3 0.05 7.3 53.7 3844.3 1 25 f 39 OD 34 HM 7.0 54.3 24440.2 1 n.f. n.f. OS 34 1/60 10.6 77.6 1245.6 1 26 f 27 OD 2 0.2 0.0 91.8 127.4 1 17 G863A 28 Q1412X OS 2 0.6 0.0 94.9 69.2 1 27 m 25 OD 1 0.3 0.0 70.7 5670.4 1 n.f. n.f. OS 1 0.4 0.0 75.6 764.9 1 28 m 17 OD 3 0.2 0.8 67.3 4244.1 1 - - - - OS 3 0.3 0.0 80.6 2429.2 1 29 m 28 OD 2,5 0.1 5.4 80.8 795.0 1 - - - - OS 2,5 0.1 4.2 64.3 2101.1 1 30 f 27 OD 20 0.1 6.7 88.2 183.6 1 G1961E G1961E OS 20 0.1 10.9 81.0 448.2 1 Dis. dur., disease duration (years); HM, recognition of hand movements; VA, visual acuity in European decimals. Login to comment

[hide] Progressive cone and cone-rod dystrophies: phenoty... Surv Ophthalmol. 2006 May-Jun;51(3):232-58. Michaelides M, Hardcastle AJ, Hunt DM, Moore AT
Progressive cone and cone-rod dystrophies: phenotypes and underlying molecular genetic basis.
Surv Ophthalmol. 2006 May-Jun;51(3):232-58., [PMID:16644365]

Abstract [show]
The cone and cone-rod dystrophies form part of a heterogeneous group of retinal disorders that are an important cause of visual impairment in children and adults. There have been considerable advances made in recent years in our understanding of the pathogenesis of these retinal dystrophies, with many of the chromosomal loci and causative genes having now been identified. Mutations in 12 genes, including GUCA1A, peripherin/RDS, ABCA4 and RPGR, have been described to date; and in many cases detailed functional assessment of the effects of the encoded mutant proteins has been undertaken. This improved knowledge of disease mechanisms has raised the possibility of future treatments for these disorders, for which there are no specific therapies available at the present time.

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235 In the first group of 12 subjects, four harbored an Ala1038Val change, one of the most common ABCA4 variants observed in Stargardt disease (STGD). Login to comment

[hide] Correlation of clinical and genetic findings in Hu... Invest Ophthalmol Vis Sci. 2005 Dec;46(12):4402-8. Hargitai J, Zernant J, Somfai GM, Vamos R, Farkas A, Salacz G, Allikmets R
Correlation of clinical and genetic findings in Hungarian patients with Stargardt disease.
Invest Ophthalmol Vis Sci. 2005 Dec;46(12):4402-8., [PMID:16303926]

Abstract [show]
PURPOSE: Autosomal recessive Stargardt disease (arSTGD) presents with substantial clinical and genetic heterogeneity. This study was conducted to correlate foveolar thickness (FT) and total macular volume (TMV), measured by optical coherence tomography (OCT), with other clinical characteristics and with specific genetic variation in Hungarian patients with arSTGD. METHODS: After a standard ophthalmic workup, both eyes of 35 patients with STGD from Hungary and of 25 age-matched healthy control subjects were tested with OCT. FT and TMV were measured automatically with the OCT mapping software in the nine Early Treatment Diabetic Retinopathy Study areas of 3500 microm in diameter. All patients were screened for mutations by a combination of the ABCR400 microarray and direct sequencing. RESULTS: The patients with STGD presented with markedly thinned retina in the foveola and decreased macular volume, 72 microm and 1.69 mm3, respectively, compared with 169 microm and 2.48 mm3 in the normal subjects, respectively. Statistically significant correlation was observed between visual acuity (VA) and TMV and between VA and FT. Disease-associated mutations were detected in 23 (65.7%) of 35 patients, including 48.5% with both alleles and 17.2% with one allele. The most frequent ABCA4 alleles in Hungarian patients with STGD were L541P/A1038V (in 28% of all patients), G1961E (20%) and IVS40+5G-->A (17%). Specific genotypes correlated with some phenotypic features and allowed for predictions of the disease progression. CONCLUSIONS: Hungarian patients with STGD presented with extensive foveolar thinning and macular volume loss. Genetic analysis detected several ABCA4 alleles at high frequency in the cohort of patients, suggesting founder effect(s). Unusually homogeneous distribution of disease-associated mutations aided genotype-phenotype correlation analyses in this population.

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11 The most frequent ABCA4 alleles in Hungarian patients with STGD were L541P/A1038V (in 28% of all patients), G1961E (20%) and IVS40ϩ5G3A (17%). Login to comment
82 The most frequent ABCA4 allele in the Hungarian STGD population was the complex allele L541P/A1038V at 14.3% (i.e., 28% of all screened patients carried at least one allele). Login to comment
89 Summarized Clinical and Genetic Data of Patients with STGD Patient Allele 1 Allele 2 Fishman OU Gender Age Duration VA OD VA OS FT OD (␮m) FT OS (␮m) MV OD (mm3 ) MV OS (mm3 ) 1 ND ND I M 18 10 0.42 0.50 90.00 76.00 1.70 1.67 2 L541P/A1038V ND III F 27 15 0.06 0.08 43.00 58.00 1.27 1.28 3 5917delG 5917delG II F 29 8 0.17 0.17 54.00 20.00 1.38 1.35 4 ND ND III F 42 14 0.10 0.10 91.00 71.00 1.60 1.59 5 V2050L ND II F 22 5 0.20 0.33 28.00 77.00 1.64 1.68 6 ND ND II F 17 2 1.00 0.71 156.00 141.00 2.55 2.6 7 IVS40ϩ5GϾA ND III M 28 13 0.10 0.06 71.00 92.00 1.61 1.61 8 L541P/A1038V G1961E II M 37 15 0.10 0.10 87.00 97.00 1.95 1.95 9 106delT G1961E II M 32 7 0.08 0.08 51.00 32.00 1.59 1.66 10 ND ND I F 55 17 0.25 0.56 160.00 170.00 1.72 1.82 11 L541P/A1038V G863A II F 15 3 0.25 0.33 67.00 68.00 1.78 1.76 12 IVS40ϩ5GϾA 5917delG III M 15 6 0.20 0.20 107.00 117.00 1.93 1.92 13 ND ND I M 27 2 0.38 0.33 56.00 86.00 2.01 1.97 14 G1886E G1961E II F 37 9 0.12 0.16 92.00 46.00 1.55 1.59 15 G1961E ND III F 20 5 0.30 0.20 49.00 34.00 1.43 1.53 16 ND ND II M 28 14 0.32 0.08 52.00 60.00 1.46 1.52 17 IVS40ϩ5GϾA 5917delG III M 27 5 0.10 0.10 97.00 92.00 1.76 1.71 18 L541P/A1038V D1532N III M 28 12 0.25 0.10 49.00 46.00 1.83 1.86 19 ND ND II F 31 11 0.10 0.13 67.00 72.00 1.55 1.49 20 L541P L541P/A1038V II F 15 5 0.10 0.10 28.00 34.00 1.63 1.65 21 L541P/A1038V G863A II F 25 2 0.20 0.62 94.00 81.00 1.92 1.94 22 L541P/A1038V ND II M 18 9 0.08 0.10 63.00 72.00 1.40 1.43 23 G1961E ND III F 34 9 0.16 0.16 16.00 23.00 1.31 1.56 24 ND ND II F 52 14 0.16 0.16 122.00 113.00 1.90 1.99 25 P68L L541P/A1038V III M 37 22 0.10 0.12 40.00 40.00 1.41 1.42 26 ND ND II F 18 11 0.20 0.25 59.00 72.00 1.42 1.47 27 L541P/A1038V G1961E II F 24 7 0.18 0.18 83.00 100.00 1.72 1.77 28 IVS40ϩ5GϾA 5917delG III M 15 7 0.10 0.16 38.00 46.00 1.30 1.41 29 R1108C R1108C II M 31 14 0.10 0.10 41.00 44.00 1.95 1.96 30 G1961E ND II M 28 6 0.33 0.56 91.00 129.00 1.98 2.04 31 ND ND II F 28 11 0.08 0.10 55.00 63.00 1.52 1.59 32 L541P/A1038V G863A II M 32 15 0.20 0.20 92.00 86.00 1.80 1.75 33 ND ND II F 27 4 0.25 0.20 66.00 75.00 1.72 1.76 34 ND ND II F 36 8 0.12 0.10 58.00 69.00 1.59 1.56 35 IVS40ϩ5GϾA IVS40ϩ5GϾA III F 19 6 0.10 0.10 62.00 53.00 1.67 1.65 Fishman OU, classification of patients by fundus photos in three categories according to Fishman et al.25 ND, not determined. Login to comment
94 However, when coupled with a deleterious variant such as the 5917delG mutation, it seems to result in a more severe phenotype.21 Patients with the L541P/A1038V complex allele were classified as phenotype II in 70% (7/10) of cases, the rest (3/10) as belonging to the phenotype III group (Table 1). Login to comment
97 In patients compound heterozygous for the L541P/ A1038V and G863A alleles (patients 11, 21, 32), a decrease in vision with the duration of the disease was observed. Login to comment
131 First, patients with the G1961E mutation, although classified in phenotype groups II and III, show the slowest progression of the TMV loss. Login to comment
132 Therefore, patients with STGD with the G1961E variant have, in general, a better than average disease prognosis. Login to comment
133 This observation is supported by two earlier re- ports20,25 and could be explained by the fact that although the G1961E variant had a drastic effect on ATPase activity, it was comparable to the wild-type protein in yield.8 Second, patients with the L541P/A1038V complex allele have, near the average in all patients with STGD, a moderate rate of disease progression. Login to comment
134 In in vitro studies, the L541P/ A1038V variant demonstrated a reduced, but not completely abolished, ATPase activity.20 The subgroup of patients, compound heterozygous for the L541P/A1038V and G863A alleles, show a better prognosis (i.e., a slower progression of the disease). Login to comment
80 The most frequent ABCA4 allele in the Hungarian STGD population was the complex allele L541P/A1038V at 14.3% (i.e., 28% of all screened patients carried at least one allele). Login to comment
87 Summarized Clinical and Genetic Data of Patients with STGD Patient Allele 1 Allele 2 Fishman OU Gender Age Duration VA OD VA OS FT OD (òe;m) FT OS (òe;m) MV OD (mm3 ) MV OS (mm3 ) 1 ND ND I M 18 10 0.42 0.50 90.00 76.00 1.70 1.67 2 L541P/A1038V ND III F 27 15 0.06 0.08 43.00 58.00 1.27 1.28 3 5917delG 5917delG II F 29 8 0.17 0.17 54.00 20.00 1.38 1.35 4 ND ND III F 42 14 0.10 0.10 91.00 71.00 1.60 1.59 5 V2050L ND II F 22 5 0.20 0.33 28.00 77.00 1.64 1.68 6 ND ND II F 17 2 1.00 0.71 156.00 141.00 2.55 2.6 7 IVS40af9;5Gb0e;A ND III M 28 13 0.10 0.06 71.00 92.00 1.61 1.61 8 L541P/A1038V G1961E II M 37 15 0.10 0.10 87.00 97.00 1.95 1.95 9 106delT G1961E II M 32 7 0.08 0.08 51.00 32.00 1.59 1.66 10 ND ND I F 55 17 0.25 0.56 160.00 170.00 1.72 1.82 11 L541P/A1038V G863A II F 15 3 0.25 0.33 67.00 68.00 1.78 1.76 12 IVS40af9;5Gb0e;A 5917delG III M 15 6 0.20 0.20 107.00 117.00 1.93 1.92 13 ND ND I M 27 2 0.38 0.33 56.00 86.00 2.01 1.97 14 G1886E G1961E II F 37 9 0.12 0.16 92.00 46.00 1.55 1.59 15 G1961E ND III F 20 5 0.30 0.20 49.00 34.00 1.43 1.53 16 ND ND II M 28 14 0.32 0.08 52.00 60.00 1.46 1.52 17 IVS40af9;5Gb0e;A 5917delG III M 27 5 0.10 0.10 97.00 92.00 1.76 1.71 18 L541P/A1038V D1532N III M 28 12 0.25 0.10 49.00 46.00 1.83 1.86 19 ND ND II F 31 11 0.10 0.13 67.00 72.00 1.55 1.49 20 L541P L541P/A1038V II F 15 5 0.10 0.10 28.00 34.00 1.63 1.65 21 L541P/A1038V G863A II F 25 2 0.20 0.62 94.00 81.00 1.92 1.94 22 L541P/A1038V ND II M 18 9 0.08 0.10 63.00 72.00 1.40 1.43 23 G1961E ND III F 34 9 0.16 0.16 16.00 23.00 1.31 1.56 24 ND ND II F 52 14 0.16 0.16 122.00 113.00 1.90 1.99 25 P68L L541P/A1038V III M 37 22 0.10 0.12 40.00 40.00 1.41 1.42 26 ND ND II F 18 11 0.20 0.25 59.00 72.00 1.42 1.47 27 L541P/A1038V G1961E II F 24 7 0.18 0.18 83.00 100.00 1.72 1.77 28 IVS40af9;5Gb0e;A 5917delG III M 15 7 0.10 0.16 38.00 46.00 1.30 1.41 29 R1108C R1108C II M 31 14 0.10 0.10 41.00 44.00 1.95 1.96 30 G1961E ND II M 28 6 0.33 0.56 91.00 129.00 1.98 2.04 31 ND ND II F 28 11 0.08 0.10 55.00 63.00 1.52 1.59 32 L541P/A1038V G863A II M 32 15 0.20 0.20 92.00 86.00 1.80 1.75 33 ND ND II F 27 4 0.25 0.20 66.00 75.00 1.72 1.76 34 ND ND II F 36 8 0.12 0.10 58.00 69.00 1.59 1.56 35 IVS40af9;5Gb0e;A IVS40af9;5Gb0e;A III F 19 6 0.10 0.10 62.00 53.00 1.67 1.65 Fishman OU, classification of patients by fundus photos in three categories according to Fishman et al.25 ND, not determined. Login to comment
92 However, when coupled with a deleterious variant such as the 5917delG mutation, it seems to result in a more severe phenotype.21 Patients with the L541P/A1038V complex allele were classified as phenotype II in 70% (7/10) of cases, the rest (3/10) as belonging to the phenotype III group (Table 1). Login to comment
95 In patients compound heterozygous for the L541P/ A1038V and G863A alleles (patients 11, 21, 32), a decrease in vision with the duration of the disease was observed. Login to comment

[hide] ABCA4 mutations causing mislocalization are found ... Hum Mol Genet. 2005 Oct 1;14(19):2769-78. Epub 2005 Aug 15. Wiszniewski W, Zaremba CM, Yatsenko AN, Jamrich M, Wensel TG, Lewis RA, Lupski JR
ABCA4 mutations causing mislocalization are found frequently in patients with severe retinal dystrophies.
Hum Mol Genet. 2005 Oct 1;14(19):2769-78. Epub 2005 Aug 15., [PMID:16103129]

Abstract [show]
ABCA4, also called ABCR, is a retinal-specific member of the ATP-binding cassette (ABC) family that functions in photoreceptor outer segments as a flipase of all-trans retinal. Homozygous and compound heterozygous ABCA4 mutations are associated with various autosomal recessive retinal dystrophies, whereas heterozygous ABCA4 mutations have been associated with dominant susceptibility to age-related macular degeneration in both humans and mice. We analyzed a cohort of 29 arRP families for the mutations in ABCA4 with a commercial microarray, ABCR-400 in addition to direct sequencing and segregation analysis, and identified both mutant alleles in two families (7%): compound heterozygosity for missense (R602W) and nonsense (R408X) alleles and homozygosity for a complex [L541P; A1038V] allele. The missense mutations were analyzed functionally in the photoreceptors of Xenopus laevis tadpoles, which revealed mislocalization of ABCA4 protein. These mutations cause retention of ABCA4 in the photoreceptor inner segment, likely by impairing correct folding, resulting in the total absence of physiologic protein function. Patients with different retinal dystrophies harboring two misfolding alleles exhibit early age-of-onset (AO) (5-12 years) of retinal disease. Our data suggest that a class of ABCA4 mutants may be an important determinant of the AO of disease.

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2 We analyzed a cohort of 29 arRP families for the mutations in ABCA4 with a commercial microarray, ABCR-400 in addition to direct sequencing and segregation analysis, and identified both mutant alleles in two families (7%): compound heterozygosity for missense (R602W) and nonsense (R408X) alleles and homozygosity for a complex [L541P; A1038V] allele. Login to comment
26 Functional studies of missense alleles [L541P; A1038V], R602W and C1490Y in transgenic frogs demonstrate that they do not translocate to rod OSs (ROSs). Login to comment
33 The sequence analysis of ABCA4 in patients AR197-05 and AR197-06 revealed homozygosity for the complex ABCA4 allele [L541P; A1038V]. Login to comment
44 A WT 168-05 24 20/25 OD; 20/30 OS;VF , 308 OU RP N/A N/A 168-06 26 N/A RP N/A N/A AR192 192-03 9 20/20 OD; 20/25 OS;VF , 58 OU RP D2177N WT 192-04 19 20/30 OD; 20/40 OS;VF , 58 OU RP WT WT 192-05 19 20/30 OD; 20/40 OS;VF , 58 OU RP WT WT AR194 194-03 30 N/A RP D2177N WT 194-05 Childhood 20/25 OD; 20/40 OS RP N/A N/A 194-06 5 N/A RP D2177N WT 194-07 4 or 5 20/80 OU RP N/A N/A AR197 197-05 7 CF 3 feet OD; CF 2 feet OS RP [L541P; A1038V] [L541P; A1038V] 197-06 9 CF 5 feet OD; HM OS RP [L541P; A1038V] [L541P; A1038V] AR554 554-03 2 10/12 20/60 OU RP V2050L WT 554-04 1 9/12 N/A RP N/A N/A AR591 591-03 20 20/25 OU RP N/A N/A 591-04 8 20/20 OD; 20/25 OS;VF , 108 OU RP G1961E WT AR689 689-03 7 N/A RP R408X R602W 689-08 7 N/A RP N/A N/A OD, right eye; OS, left eye; OU, both eyes; VF, visual field; RP, retinitis pigementosa, WT, wild type; N/A, not available; CF, counting fingers; HM, hand motions. Login to comment
80 (C-L) Microphotographs of 2-week-old X. laevis tadpoles expressing R602W (C and D), [L541P; A1038V] (E and F), L541P (G and H), A1038V (I and J) and C1490Y (K and L). Login to comment
81 Rod photoreceptors expressing each of the mutant proteins, except A1038V, demonstrated localization of the transgenic protein to the rod inner segment and cell body. Login to comment
83 Mutation A1038V does not influence the localization of ABCA4 and the mutant protein was found in the ROS. Login to comment
92 Functional studies of the arRP-associated complex allele [L541P; A1038V] also showed abnormal localization to rod IS although the IF studies revealed a different staining pattern than R602W, because the mutant protein forms fine aggregates in the IS (Fig. 2E and F). Login to comment
93 The aggregate formation suggests a mechanism distinct from that observed for R602W may be responsible for the retention of [L541P; A1038V] in the IS. Login to comment
94 To determine which mutation prevents translocation of [L541P; A1038V] to ROS, we examined functionally the L541P and A1038V mutants independently. Login to comment
95 We observed retention of L541P in the IS (Fig. 2G and H) and correct localization of A1038V to ROS (Fig. 2I and J). Login to comment
104 We employed this assay to examine the effects of [L541P; A1038V], R602W and C1490Y mutations on in vitro ATP hydrolysis. Login to comment
107 The rate of ATP hydrolysis of the complex allele [L541P; A1038V] was decreased to 68.1% of wild-type ABCA4 (Fig. 3). Login to comment
112 Decreased ATPase activity does not likely contribute to the overall pathogenicity of [L541P; A1038V] because localization to the ROS is the primary event that determines placement of the protein in its natural environment and is presumably required for it to perform its physiological function. Login to comment
113 Mutations: R602W, [L541P; A1038V] and C1490Y are frequently detected in patients with retinal diseases Mislocalization mutations R602W, [L541P; A1038V] and C1490Y have been reported as disease-associated mutations in patients with RP, CRD and STGD (18,20,32,33). Login to comment
119 WT and mutant constructs [L541P; A1038V], R602W and C1490Y ABCA4 were expressed in COS7 cells. Login to comment
136 Co-segregating compound heterozygous mutant alleles (R602W/R408X) and a homozygous complex allele [L541P; A1038V] were identified in two (AR689 and AR197) arRP families (Table 1). Login to comment
137 We hypothesized that the disease-associated missense mutations [L541P; A1038V], R602W and C1490Y could exert a possible effect on protein processing as this mechanism, which prevents altered proteins from locating to its physiologic compartment, was documented for other ABC transporters in related diseases including cystic fibrosis (CFTR) and Tangier disease (ABCA1). Login to comment
138 To examine this hypothesis, we generated transgenic X. laevis tadpoles expressing WT, [L541P; A1038V], R602W and C1490Y mutants and documented that the three mutant alleles cause mislocalization of ABCA4. Login to comment
146 Genotype-phenotype correlations among patients bearing one and two mislocalization-mutations Two mislocalization-alleles One mislocalization-allele RP STGD Allele 1 Allele 2 AO Allele 1 Allele 2 AO [L541P; A1038V] [L541P; A1038V] 7 [L541P; A1038V] L2027F 13 [L541P; A1038V] [L541P; A1038V] 9 [L541P; A1038V] R1108H 13 [L541P; A1038V] G1961E 16 CRD [L541P; A1038V] G1961E 28 Allele 1 Allele 2 AO [L541P; A1038V] L2027F 13 [L541P; A1038V] [L541P; A1038V] 10 [L541P; A1038V] L2027F 12 [L541P; A1038V] C1490Y 12 [L541P; A1038V] P1380L 5 R602W R602W 7 [L541P; A1038V] T1019M 6 [L541P; A1038V] G1961E 7 STGD [L541P; A1038V] T1019M 6 Allele 1 Allele 2 AO R602W L2027F 9 [L541P; A1038V] [L541P; A1038V] 12 C1490Y G1961E 28 C1490Y C1490Y 7 C1490Y G1961E 13 C1490Y R602W 9 C1490Y L2027F 10 C1490Y R602W 10 C1490Y L2027F 18 C1490 L2027F 18 AO-age of onset (in years). Login to comment
150 The results of IF studies of rods expressing [L541P; A1038V], R602W and C1490Y mutants were quite distinct from those observed for WT and ABCA4 EGFP. Login to comment
152 We also identified that L541P is responsible for the retention of the complex allele [L541P; A1038V], whereas A1038V seems to have no effect on ABCA4 processing. Login to comment
165 Presumed folding mutations, especially [L541P; A1038V] and C1490Y, have been frequently detected in patients with autosomal recessive macular degenerations (18,20,32,33). Login to comment
179 Shown is a proposed topological model of ABCA4 with its membrane spanning domains and the mutations: L541P, R602W, A1038V and C1490 analyzed. Login to comment
199 To generate the retinal dystrophy associated ABCA4 alleles: [L541P; A1038V], L541P, A1038V, R602W and C1490Y ABCA4, the pXOP-ABCA4 plasmid was mutagenized with Quickchange PCR-based mutagenesis system (Biocrest, La Jolla, CA, USA). Login to comment
228 In particular, we searched for subjects with RP, CRD and STGD in whom two mislocalization-mutant alleles [L541P; A1038V], R602W and C1490Y] were detected. Login to comment

[hide] Evolution of ABCA4 proteins in vertebrates. J Mol Evol. 2005 Jan;60(1):72-80. Yatsenko AN, Wiszniewski W, Zaremba CM, Jamrich M, Lupski JR
Evolution of ABCA4 proteins in vertebrates.
J Mol Evol. 2005 Jan;60(1):72-80., [PMID:15696369]

Abstract [show]
The ABCA4 (ABCR) gene encodes a retinal-specific ATP-binding cassette transporter. Mutations in ABCA4 are responsible for several recessive macular dystrophies and susceptibility to age related macular degeneration (AMD). The protein appears to function as a flippase of all-trans-retinaldehyde and/or its derivatives across the membrane of outer segment disks and is a potentially important element in recycling visual cycle metabolites. However, the understanding of ABCA4's role in the visual cycle is limited due to the lack of a direct functional assay. An evolutionary analysis of ABCA4 may aid in the identification of conserved elements, the preservation of which implies functional importance. To date, only human, murine, and bovine ABCA4 genes are described. We have identified ABCA4 genes from African (Xenopus laevis) and Western (Silurana tropicalis) clawed frogs. A comparative analysis describing the evolutionary relationships between the frog ABCA4s, annotated T. rubripes ABCA4, and mammalian ABCA4 proteins was carried out. Several segments are conserved in both intradiscal loop (IL) domains, in addition to the transmembrane and ATP-binding domains. Nonconserved segments were found in the IL and cytoplasmic linker domains. Maximum likelihood analyses of the aligned sequences strongly suggest that ABCA4 was subject to purifying selection. Collectively, these data corroborate the current evolutionary model where two distinct ABCA half-transporter progenitors were combined to form a full ABCA4 progenitor in ancestral chordates. We speculate that evolutionary alterations may increase the retinoid metabolite recycling capacity of ABCA4 and may improve dark adaptation.

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130 As anticipated, the most frequently occurring STGD- associated missense ABCA4 alterations (R212C, L541P, D645N, G863A, A1038V, R1108C, R1380L, W1408R, T1526M, R1640W, G1961E, L2027F, and L2030Q) map to highly conserved regions. Login to comment

[hide] Microarray-based mutation analysis of the ABCA4 (A... Eur J Hum Genet. 2004 Dec;12(12):1024-32. Klevering BJ, Yzer S, Rohrschneider K, Zonneveld M, Allikmets R, van den Born LI, Maugeri A, Hoyng CB, Cremers FP
Microarray-based mutation analysis of the ABCA4 (ABCR) gene in autosomal recessive cone-rod dystrophy and retinitis pigmentosa.
Eur J Hum Genet. 2004 Dec;12(12):1024-32., [PMID:15494742]

Abstract [show]
Mutations in the ABCA4 gene have been associated with autosomal recessive Stargardt disease (STGD1), cone-rod dystrophy (CRD), and retinitis pigmentosa (RP). We employed a recently developed genotyping microarray, the ABCR400-chip, to search for known ABCA4 mutations in patients with isolated or autosomal recessive CRD (54 cases) or RP (90 cases). We performed detailed ophthalmologic examinations and identified at least one ABCA4 mutation in 18 patients (33%) with CRD and in five patients (5.6%) with RP. Single-strand conformation polymorphism (SSCP) analysis and subsequent DNA sequencing revealed four novel missense mutations (R24C, E161K, P597S, G618E) and a novel 1-bp deletion (5888delG). Ophthalmoscopic abnormalities in CRD patients ranged from minor granular pigmentary changes in the posterior pole to widespread atrophy. In 12 patients with recordable electroretinogram (ERG) tracings, a cone-rod pattern was detected. Three patients demonstrated progression from a retinal dystrophy resembling STGD1 to a more widespread degeneration, and were subsequently diagnosed as CRD. In addition to a variable degree of atrophy, all RP patients displayed ophthalmologic characteristics of classic RP. When detectable, ERG recordings in these patients demonstrated rod-cone patterns of photoreceptor degeneration. In conclusion, in this study, we show that the ABCA4 mutation chip is an efficient first screening tool for arCRD.

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57 Table 1 ABCA4 sequence variants in CRD patients CRD patient number Inheritance Allele 1 Allele 2 Mutations segregateNucleotide change Effect Nucleotide change Effect 12608 Isolated IVS38-10T4C Unknowna IVS38-10T4C Unknowna Yes 14488 Isolated 1622T4C; 3113C4T L541P; A1038V Not identified NA 14750 Isolated 4918C4T R1640W Not identified NA 14752 Isolated 1622T4C; 3113C4T L541P; A1038V IVS38-10T4C Unknowna ? Login to comment
59 15428 Isolated 1622T4C; 3113C4T L541P; A1038V 2300T4A V767D ? Login to comment
62 16242 Isolated 1622T4C; 3113C4T L541P; A1038V Not identified NA 16243 Isolated 5381C4A A1794D 1789C4T P597S ? Login to comment
63 481G4A E161K 16569 Aut. rec. 3259G4A E1087K Not identified NA 16582 Isolated 1622T4C; 3113C4T L541P; A1038V IVS38-10T4C Unknowna ? Login to comment
101 Likewise, the known Table 2 ABCA4 sequence variants in RP patients RP patient number Inheritance Allele 1 Allele 2 Nucleotide change Effect Nucleotide change Effect 9304 Aut. Rec. 2588G4C; 2828G4Aa DG863/G863A; R943Q 5888delG R1963fs 9444 Aut. Rec. 6529G4A D2177N Not identified 9545 Isolated 6529G4A D2177N Not identified 14753 Isolated 1622T4C; 3113C4T L541P; A1038V Not identified 17597 Isolated 6148G4C V2050L Not identified a Polymorphic variants 4203A, 5603 T, and 5682C also present. Login to comment
143 Given this clinical presentation and the fact that homozygous null mutations were not found Table 5 Functional assessment of missense (A) and splice site (B) mutations (A) Missense mutation Nature of amino-acid change Effect on ABCR functionRef R18W Nonconservative Unknown R24C Nonconservative Unknown; adjacent to first transmembrane domain G65E Nonconservative Unknown E161K Nonconservative Unknown L541P Conservative Decreased ATP binding and ATPase activity50 P597S Nonconservative Unknown G618E Nonconservative Unknown V767D Nonconservative Decreased ABCR expression10 G863A Nonconservative Decreased ATPase activity50, 51 R943Q Nonconservative Decreased ATPase activity51 A1038V Conservative Decreased ATP binding and ATPase activity50 E1087K Nonconservative Decreased ATP binding50 V1433I Conservative Unknown R1640W Nonconservative Unknown A1794D Nonconservative Introduction charged aa in 10th transmembrane domain G1961E Nonconservative Decreased ATP binding and ATPase activity 50 V2050L Conservative Unknown D2177N Nonconservative Increased ATPase activity50 (B) Splice site mutation Effect on mRNARef Predicted effect on ABCR protein 768G4T Nonsense-mediated decay33 No protein IVS36+2T4C Unknown Truncation of exon 36 resulting in V1673fs? Login to comment

[hide] Electroretinographic findings in patients with Sta... Retina. 2004 Dec;24(6):920-8. Oh KT, Weleber RG, Stone EM, Oh DM, Rosenow J, Billingslea AM
Electroretinographic findings in patients with Stargardt disease and fundus flavimaculatus.
Retina. 2004 Dec;24(6):920-8., [PMID:15579991]

Abstract [show]
PURPOSE: To characterize the clinical and electroretinogram (ERG) features of our cohort of patients with Stargardt disease (STGD) exhibiting coding sequence variations in the ABCA4 gene. METHODS: Review of 76 patients with the clinical diagnosis of Stargardt disease/fundus flavimaculatus (STGD/FF) from the University of Iowa Department of Ophthalmology and Visual Sciences (41 patients) and the Casey Eye Institute (35 patients). Clinical examination, Goldmann perimetry, and electroretinography were performed on all 76 patients. Patients were divided into three groups on the basis of their funduscopic and electroretinographic features: (1) a normal ERG by the standards of the laboratory; (2) minimal rod or cone abnormalities; (3) severe ERG dysfunction. The latter category was further subdivided on the basis of a cone-dominated loss of function (C > R or "cone-rod dystrophy") or diffuse depression of rods and cones (C = R). Mutational analysis of the coding sequence of the ABCA4 gene was performed by single strand conformation polymorphism analysis followed by automated DNA sequencing. Each electroretinographic group was analyzed for the presence of disease causing changes using exact tests of binomial proportions corrected for multiple comparisons by Bonferroni method. Quantitative polymerase chain reaction (QPCR) was performed on patients who were homozygous for disease causing changes in the ABCA4 gene to rule out the possibility of deletions. RESULTS: Overall, 56 of 76 patients (and 77 of 152 alleles) exhibited coding sequence variations that were compatible with high-penetrance disease-causing mutations. The most common of these were His423Arg (9), frameshift mutations (7), Ala1038Val (7), and Pro1380Leu (6). Although no patients with His423Arg presented with normal ERGs, no significant correlation was observed between specific sequence variations and the electroretinographic characteristics or fundus appearance. However, a significantly greater fraction of patients with normal ERG studies failed to exhibit detectable disease-causing coding sequence variations in the ABCA4 gene identified on either allele (P = 0.0006). CONCLUSION: STGD/FF patients in our cohort exhibit a wide range of electroretinographic abnormalities, some of which are more prevalent than previously suspected. No direct correlation between clinical appearance, electrophysiologic characteristics and specific ABCA4 alleles could be identified, although a significantly lower number of our cohort with a normal ERG exhibited detectable coding sequence variations in the ABCA4 gene. However, four patients with ERG dysfunction were homozygous for a His423Arg change proven by QPCR not to be an artifact of a deletion. The presence of electrophysiologic dysfunction is not uncommon in our cohort of patients with STGD. Thus, the ERG provides clinically important information of retinal function for STGD/FF and, as such, is still indicated as part of the evaluation of these patients.

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9 The most common of these were His423Arg (9), frameshift mutations (7), Ala1038Val (7), and Pro1380Leu (6). Login to comment
165 In fact, the six most common HPRDCV, with the exception of His423Arg, (frameshift changes, Ala1038Val, Pro1380Leu, Arg1108Cys, Leu2027Phe) were observed with all three ERG classes: severe ERG derangements, mild ERG derangements, and normal ERG studies. Login to comment

[hide] Denaturing HPLC profiling of the ABCA4 gene for re... Clin Chem. 2004 Aug;50(8):1336-43. Epub 2004 Jun 10. Stenirri S, Fermo I, Battistella S, Galbiati S, Soriani N, Paroni R, Manitto MP, Martina E, Brancato R, Allikmets R, Ferrari M, Cremonesi L
Denaturing HPLC profiling of the ABCA4 gene for reliable detection of allelic variations.
Clin Chem. 2004 Aug;50(8):1336-43. Epub 2004 Jun 10., [PMID:15192030]

Abstract [show]
BACKGROUND: Mutations in the retina-specific ABC transporter (ABCA4) gene have been associated with several forms of macular degenerations. Because the high complexity of the molecular genotype makes scanning of the ABCA4 gene cumbersome, we describe here the first use of denaturing HPLC (DHPLC) to screen for ABCA4 mutations. METHODS: Temperature conditions were designed for all 50 exons based on effective separation of 83 samples carrying 86 sequence variations and 19 mutagenized controls. For validation, samples from 23 previously characterized Stargardt patients were subjected to DHPLC profiling. Subsequently, samples from a cohort of 30 patients affected by various forms of macular degeneration were subjected to DHPLC scanning under the same conditions. RESULTS: DHPLC profiling not only identified all 132 sequence alterations previously detected by double-gradient denaturing gradient gel electrophoresis but also identified 5 sequence alterations that this approach had missed. Moreover, DHPLC scanning of an additional panel of 30 previously untested patients led to the identification of 26 different mutations and 29 polymorphisms, accounting for 203 sequence variations on 29 of the 30 patients screened. In total, the DHPLC approach allowed us to identify 16 mutations that had never been reported before. CONCLUSIONS: These results provide strong support for the use of DHPLC for molecular characterization of the ABCA4 gene.

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35 Exon Genotypesa Exon Genotypesa 1b M1V (1A>G) (11) 24 3523-28TϾC (12) R18W (52C>T) (11) 25 G1203D (3608G>A)b 3 250_251insCAAA (7) 27 R1300X (3898C>T) (12) N96K (288C>A) R1300Q (3899G>A) (11) 302 ϩ 26 GϾA (13) 28 P1380L (4139CϾT) (14) 4 P143L (428C>T) (10) P1401P (4203CϾA) (15) 5 R152Q (455G>A) (4) 4253 ϩ 43GϾA (12) 6 571-1GϾT (4) 29 4253 ϩ 13GϾA (12) R212H (635G>A) (16) 4354-38GϾA (4) C230S (688T>A) (12) 30a 4466 ϩ 3GϾA (4) 641delG (9) 30b C1490Y (4469G>A) (17) 10 1240-14CϾT (13) P1512R (4535C>G) (4) H423R (1268ϾG) (13) 31 T1526M (4577C>T) (14) 1357 ϩ 11delG (16) 33/34 A1598D (4793C>A) (4) H423H (1269CϾT) (13) 35 4947delC (14) 11 1387delTT (4) 5018 ؉ 2T>C (7) R500R (1500GϾA) (4) 39 H1838Y (5512C>T) (14) 12 L541P (1622T>C) (14) 40 N1868I (5603AϾT) (13) R572Q (1715G>A) (17) L1894L (5682GϾC) (15) 13 Y639X (1917C>G) (17) 5714 ؉ 5G>A C641S (1922G>C) (4) 41 L1938L (5814AϾG) (12) 14 R653C (1957C>T) (12) 42 5836-43CϾA W700X (2099G>A) (4) 5836-11GϾA (15) 3607 ϩ 49TϾC P1948I (5843CϾT) (15) 15 V767D (2300T>A) (7) P1948P (5844AϾG) (15) 16 W821R (2461T>A) (14) G1961E (5882G>A) (14) 17 2588-33CϾTb 43 L1970F (5908C>T) (11) G863A (2588G>C) (17) 44 6006-16AϾG (16) 18 2654-36CϾT (4) I2023I (6069CϾT) (14) T897I (2690C>T) (7) L2027F (6079C>T) (14) 19 R943Q (2828GϾA) (13) 45 V2050L (6148G>C) (14) Y954D (2860T>G) (4) 46 R2107H (6320G>A) (18) N965S (2894A>G) (14) 6386 ؉ 2G>C (10) 20 G978D (2933G>A) (4) 47 R2139W (6415C>T) (14) L988L (2964CϾT) (4) R2149L (6446G>T) (4) 21 E1022K (3064G>A) (4) C2150Y (6449G>A) (19) A1038V (3113C>T) (14) 48 D2177N (6529G>A) (17) G1050D (3149G>A) (4) L2241V (6721C>G) (12) 3211_3212insGT (14) 6729 ϩ 21CϾT (15) 22 E1087K (3259G>A) (14) 49 6730-3TϾC (15) R1098C (3292C>T) (12) S2255I (6764GϾT) (13) S1099P (3295T>C) (4) 6816 ϩ 28GϾC (4) R1108C (3322C>T) (14) R1129L (3386G>T) (17) a Bold indicates disease-causing mutations. Login to comment
34 Exon Genotypesa Exon Genotypesa 1b M1V (1A>G) (11) 24 3523-28Tb0e;C (12) R18W (52C>T) (11) 25 G1203D (3608G>A)b 3 250_251insCAAA (7) 27 R1300X (3898C>T) (12) N96K (288C>A) R1300Q (3899G>A) (11) 302 af9; 26 Gb0e;A (13) 28 P1380L (4139Cb0e;T) (14) 4 P143L (428C>T) (10) P1401P (4203Cb0e;A) (15) 5 R152Q (455G>A) (4) 4253 af9; 43Gb0e;A (12) 6 571-1Gb0e;T (4) 29 4253 af9; 13Gb0e;A (12) R212H (635G>A) (16) 4354-38Gb0e;A (4) C230S (688T>A) (12) 30a 4466 af9; 3Gb0e;A (4) 641delG (9) 30b C1490Y (4469G>A) (17) 10 1240-14Cb0e;T (13) P1512R (4535C>G) (4) H423R (1268b0e;G) (13) 31 T1526M (4577C>T) (14) 1357 af9; 11delG (16) 33/34 A1598D (4793C>A) (4) H423H (1269Cb0e;T) (13) 35 4947delC (14) 11 1387delTT (4) 5018 d19; 2T>C (7) R500R (1500Gb0e;A) (4) 39 H1838Y (5512C>T) (14) 12 L541P (1622T>C) (14) 40 N1868I (5603Ab0e;T) (13) R572Q (1715G>A) (17) L1894L (5682Gb0e;C) (15) 13 Y639X (1917C>G) (17) 5714 d19; 5G>A C641S (1922G>C) (4) 41 L1938L (5814Ab0e;G) (12) 14 R653C (1957C>T) (12) 42 5836-43Cb0e;A W700X (2099G>A) (4) 5836-11Gb0e;A (15) 3607 af9; 49Tb0e;C P1948I (5843Cb0e;T) (15) 15 V767D (2300T>A) (7) P1948P (5844Ab0e;G) (15) 16 W821R (2461T>A) (14) G1961E (5882G>A) (14) 17 2588-33Cb0e;Tb 43 L1970F (5908C>T) (11) G863A (2588G>C) (17) 44 6006-16Ab0e;G (16) 18 2654-36Cb0e;T (4) I2023I (6069Cb0e;T) (14) T897I (2690C>T) (7) L2027F (6079C>T) (14) 19 R943Q (2828Gb0e;A) (13) 45 V2050L (6148G>C) (14) Y954D (2860T>G) (4) 46 R2107H (6320G>A) (18) N965S (2894A>G) (14) 6386 d19; 2G>C (10) 20 G978D (2933G>A) (4) 47 R2139W (6415C>T) (14) L988L (2964Cb0e;T) (4) R2149L (6446G>T) (4) 21 E1022K (3064G>A) (4) C2150Y (6449G>A) (19) A1038V (3113C>T) (14) 48 D2177N (6529G>A) (17) G1050D (3149G>A) (4) L2241V (6721C>G) (12) 3211_3212insGT (14) 6729 af9; 21Cb0e;T (15) 22 E1087K (3259G>A) (14) 49 6730-3Tb0e;C (15) R1098C (3292C>T) (12) S2255I (6764Gb0e;T) (13) S1099P (3295T>C) (4) 6816 af9; 28Gb0e;C (4) R1108C (3322C>T) (14) R1129L (3386G>T) (17) a Bold indicates disease-causing mutations. Login to comment

[hide] Dark adaptation of rod photoreceptors in normal su... Invest Ophthalmol Vis Sci. 2004 Jul;45(7):2447-56. Kang Derwent JJ, Derlacki DJ, Hetling JR, Fishman GA, Birch DG, Grover S, Stone EM, Pepperberg DR
Dark adaptation of rod photoreceptors in normal subjects, and in patients with Stargardt disease and an ABCA4 mutation.
Invest Ophthalmol Vis Sci. 2004 Jul;45(7):2447-56., [PMID:15223829]

Abstract [show]
PURPOSE: Psychophysical and electroretinographic (ERG) studies indicate that patients with Stargardt disease exhibit abnormally slow rod dark adaptation after illumination that bleaches a substantial fraction of rhodopsin. However, relatively little information is available concerning rod recovery in this disease after weaker adapting (i.e., conditioning) light. With the use of a paired-flash ERG method, properties of the derived rod response to a low-bleach (<1%) but rod-saturating conditioning flash were investigated in seven normal subjects and in five Stargardt patients with identified sequence variations in the ABCA4 gene. METHODS: In the first of two experiments, the interval between a fixed conditioning flash (67 or 670 scotopic cd s m(-2)) and a bright probe flash of fixed strength was varied to determine the falling-phase kinetics of the derived rod response to the conditioning flash. In the second, the instantaneous amplitude-intensity function for the rod response at an intermediate stage of recovery from the conditioning flash was determined by presenting a test flash of various strengths at a fixed time after the conditioning flash, and a probe flash at 200 ms after the test flash. RESULTS: The maximum peak amplitude of the dark-adapted, rod-mediated a-wave determined in Stargardt patients (211 +/- 87 microV) was on average lower than that determined in normal subjects (325 +/- 91 microV; P = 0.06). The derived rod response to the 670 scotopic cd s m(-2) conditioning flash determined in normal subjects and Stargardt patients exhibited a biphasic recovery, and the kinetics of the early stage of this recovery were similar in the two subject groups. For both normal subjects and patients, normalized amplitude-intensity functions describing the dark-adapted derived rod response exhibited half-saturation at approximately 1.5 log scotopic troland second. In both groups, the normalized amplitude-intensity function determined at approximately 2 seconds after the 67 scotopic cd s m(-2) conditioning flash and at approximately 9 seconds after the 670 scotopic cd s m(-2) conditioning flash exhibited an average desensitization (i.e., an increase of test flash strength at half-saturation) of approximately 0.5 to 0.6 log unit relative to that determined under dark-adapted conditions. CONCLUSIONS: The results indicate that, despite a reduction in the average dark-adapted maximum a-wave amplitude in the Stargardt/ABCA4 patients, the early-stage recovery kinetics of the derived rod response to a low-bleaching conditioning flash as well as the lingering rod desensitization produced by such a flash are similar to those determined in normal subjects.

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53 Description of Subjects Subject Number Age* Sex ABCA4 Variation Dark-Adapted Maximum Peak a-Wave Amplitude (␮V)† Normal subjects 101 55 M - -243 102 37 F - -410 103 26 M - -188 104 23 F - -397 105 56 F - -268 111 29 F - -362 112 23 M - -410 -325 Ϯ 91 Stargardt patients 106 50 F val849ala, arg2107his -201 107 41 M gly1961glu, arg2077trp -306 108 22 M ala60val, 1 bp ins codon 1513 -82 109 34 M leu541pro/ala1038val,‡ gly1961glu -277 110 51 M gly1961glu -191 -211 Ϯ 87 * Age on the date of determination of the a-wave result shown in the right-hand column. Login to comment
56 ‡ leu541pro and ala1038val are commonly found together on the same allele. Login to comment
78 All of the allelic variations in the ABCA4 gene found in these patients are significantly more prevalent in patients with Stargardt disease than in the normal population.24 The ala1038val and gly1961glu alleles are relatively common in Stargardt disease and may have altered frequencies in different populations as a result of founder effects.31 FIGURE 2. Login to comment

[hide] Mutations in ABCA4 result in accumulation of lipof... Hum Mol Genet. 2004 Mar 1;13(5):525-34. Epub 2004 Jan 6. Cideciyan AV, Aleman TS, Swider M, Schwartz SB, Steinberg JD, Brucker AJ, Maguire AM, Bennett J, Stone EM, Jacobson SG
Mutations in ABCA4 result in accumulation of lipofuscin before slowing of the retinoid cycle: a reappraisal of the human disease sequence.
Hum Mol Genet. 2004 Mar 1;13(5):525-34. Epub 2004 Jan 6., [PMID:14709597]

Abstract [show]
Mutations in ABCA4, which encodes a photoreceptor specific ATP-binding cassette transporter (ABCR), cause autosomal recessive forms of human blindness due to retinal degeneration (RD) including Stargardt disease. The exact disease sequence leading to photoreceptor and vision loss in ABCA4-RD is not known. Extrapolation from murine and in vitro studies predicts that two of the earliest pathophysiological features resulting from disturbed ABCR function in man would be slowed kinetics of the retinoid cycle and accelerated deposition of lipofuscin in the retinal pigment epithelium (RPE). To determine the human pathogenetic sequence, we studied surrogate measures of retinoid cycle kinetics, lipofuscin accumulation, and rod and cone photoreceptor and RPE loss in ABCA4-RD patients with a wide spectrum of disease severities. There were different extents of photoreceptor/RPE loss and lipofuscin accumulation in different regions of the retina. Slowing of retinoid cycle kinetics was not present in all patients; when present, it was not homogeneous across the retina; and the extent of slowing correlated well with the degree of degeneration. The orderly relationship between these phenotypic features permitted the development of a model of disease sequence in ABCA4-RD. The model predicted lipofuscin accumulation as a key and early component of the disease expression in man, as in mice. In man, however, abnormal slowing of the rod and cone retinoid cycle occurs at later stages of the disease sequence. Knowledge of the human ABCA4 disease sequence will be critical for defining rates of progression, selecting appropriate patients and retinal locations for future therapy, and choosing appropriate treatment outcomes.

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47 Alleles demonstrated to have major abnormalities in vitro (7) could result in mild disease (P10: E1087K/G1961E) or severe disease (P5: G818E/ L541Pþ A1038V; or P9: N965S/N965S). Login to comment

[hide] Association of a homozygous nonsense mutation in t... Ophthalmic Res. 2004 Mar-Apr;36(2):82-8. Simonelli F, Testa F, Zernant J, Nesti A, Rossi S, Rinaldi E, Allikmets R
Association of a homozygous nonsense mutation in the ABCA4 (ABCR) gene with cone-rod dystrophy phenotype in an Italian family.
Ophthalmic Res. 2004 Mar-Apr;36(2):82-8., [PMID:15017103]

Abstract [show]
Genetic variation in the ABCA4 (ABCR) gene has been associated with several distinct retinal phenotypes, including Stargardt disease/fundus flavimaculatus (STGD/FFM), cone-rod dystrophy (CRD), retinitis pigmentosa (RP) and age-related macular degeneration. The current model of genotype/phenotype association suggests that patients harboring deleterious mutations in both ABCR alleles would develop RP-like retinal pathology. Here we describe ABCA4-associated phenotypes, including a proband with a homozygous nonsense mutation in a family from Southern Italy. The proband had been originally diagnosed with STGD. Ophthalmologic examination included kinetic perimetry, electrophysiological studies and fluorescein angiography. DNA of the affected individual and family members was analyzed for variants in all 50 exons of the ABCA4 gene by screening on the ABCR400 microarray. A homozygous nonsense mutation 2971G>T (G991X) was detected in a patient initially diagnosed with STGD based on funduscopic evidence, including bull's eye depigmentation of the fovea and flecks at the posterior pole extending to the mid-peripheral retina. Since this novel nucleotide substitution results in a truncated, nonfunctional, ABCA4 protein, the patient was examined in-depth for the severity of the disease phenotype. Indeed, subsequent electrophysiological studies determined severely reduced cone amplitude as compared to the rod amplitude, suggesting the diagnosis of CRD. ABCR400 microarray is an efficient tool for determining causal genetic variation, including new mutations. A homozygous protein-truncating mutation in ABCA4 can cause a phenotype ranging from STGD to CRD as diagnosed at an early stage of the disease. Only a combination of comprehensive genotype/phenotype correlation studies will determine the proper diagnosis and prognosis of ABCA4-associated pathology.

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89 Finally, a homozygous complex allele L541P/A1038V has been associated with both CRD [13] and STGD [32] phenotype. Login to comment

[hide] Genotyping microarray (gene chip) for the ABCR (AB... Hum Mutat. 2003 Nov;22(5):395-403. Jaakson K, Zernant J, Kulm M, Hutchinson A, Tonisson N, Glavac D, Ravnik-Glavac M, Hawlina M, Meltzer MR, Caruso RC, Testa F, Maugeri A, Hoyng CB, Gouras P, Simonelli F, Lewis RA, Lupski JR, Cremers FP, Allikmets R
Genotyping microarray (gene chip) for the ABCR (ABCA4) gene.
Hum Mutat. 2003 Nov;22(5):395-403., [PMID:14517951]

Abstract [show]
Genetic variation in the ABCR (ABCA4) gene has been associated with five distinct retinal phenotypes, including Stargardt disease/fundus flavimaculatus (STGD/FFM), cone-rod dystrophy (CRD), and age-related macular degeneration (AMD). Comparative genetic analyses of ABCR variation and diagnostics have been complicated by substantial allelic heterogeneity and by differences in screening methods. To overcome these limitations, we designed a genotyping microarray (gene chip) for ABCR that includes all approximately 400 disease-associated and other variants currently described, enabling simultaneous detection of all known ABCR variants. The ABCR genotyping microarray (the ABCR400 chip) was constructed by the arrayed primer extension (APEX) technology. Each sequence change in ABCR was included on the chip by synthesis and application of sequence-specific oligonucleotides. We validated the chip by screening 136 confirmed STGD patients and 96 healthy controls, each of whom we had analyzed previously by single strand conformation polymorphism (SSCP) technology and/or heteroduplex analysis. The microarray was >98% effective in determining the existing genetic variation and was comparable to direct sequencing in that it yielded many sequence changes undetected by SSCP. In STGD patient cohorts, the efficiency of the array to detect disease-associated alleles was between 54% and 78%, depending on the ethnic composition and degree of clinical and molecular characterization of a cohort. In addition, chip analysis suggested a high carrier frequency (up to 1:10) of ABCR variants in the general population. The ABCR genotyping microarray is a robust, cost-effective, and comprehensive screening tool for variation in one gene in which mutations are responsible for a substantial fraction of retinal disease. The ABCR chip is a prototype for the next generation of screening and diagnostic tools in ophthalmic genetics, bridging clinical and scientific research.

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30 What makes ABCR a more difficult diagnostic target than CFTR is that the most frequent disease-associated ABCR alleles, e.g., 5882G>A (G1961E), 2588G>C (G863A/ delG863), and 3113C>T (A1038V), have each been described in only B10% of STGD patients in a distinct population, whereas the delF508 allele of CFTR accounts for close to 70% of all cystic fibrosis alleles [Zielenski and Tsui, 1995]. Login to comment

[hide] ABCA4 gene sequence variations in patients with au... Arch Ophthalmol. 2003 Jun;121(6):851-5. Fishman GA, Stone EM, Eliason DA, Taylor CM, Lindeman M, Derlacki DJ
ABCA4 gene sequence variations in patients with autosomal recessive cone-rod dystrophy.
Arch Ophthalmol. 2003 Jun;121(6):851-5., [PMID:12796258]

Abstract [show]
OBJECTIVE: To identify sequence variations in the ABCA4 gene in a cohort of patients with autosomal recessive cone-rod dystrophy. METHODS: The coding sequences of the ABCA4 gene were analyzed in 30 unrelated probands. In those patients with plausible disease-causing variations, correlations were made between genotype and fundus phenotype as well as with electrophysiological and visual field findings. RESULTS: Sixteen (53%) of 30 probands were found to harbor plausible disease-causing variations in the ABCA4 gene. Two distinctly different fundus phenotypes were observed in our cohort of patients. Twelve patients showed diffuse pigmentary degenerative changes, whereas 4 showed either no pigmentary changes or only a mild degree of peripheral pigment degeneration. An associa-tion between certain sequence variations and each of these 2 different phenotypes was observed. CONCLUSIONS: Our findings confirm that a substantial percentage of patients with autosomal recessive cone-rod dystrophy are likely to harbor a mutation in the ABCA4 gene as the cause of their disease. The fundus phenotype observed in such patients is quite variable, and certain fundus phenotypes may be more associated with certain genotypes. Clinical Relevance Identification of the molecular genetic basis for various inherited human retinal dystrophies, such as cone-rod dystrophy, facilitates a potentially better understanding of the mechanisms by which photoreceptor cells degenerate. This in turn provides guidance as to how to better proceed in identifying the most optimal future therapeutic strategies.

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59 Of the 12 patients with diffuse pigmentary changes (type 1), 4 harbored an Ala1038Val change, which is the second most common ABCA4 variant we have observed in patients with Stargardt disease.19 Two of these 4 patients were African American. Login to comment
80 Twelve patients exhibited a fundus phenotype consisting of diffuse pigmentary changes, and 4 of these harbored an Ala1038Val change, one of the most common ABCA4 variants observed in patients with Stargardt disease. Login to comment
83 Maugeri et al10 commented that a complex allele consisting of Ala1038Val and Leu541Pro variations on the same allele was found exclusively in their German patients (6 of 14). Login to comment
94 Patients With Cone-Rod Dystrophy Patient No./ Age, y/Sex Race/ Ethnicity Visual Acuity Visual Field Fundus Type* Mutation Cone vs Rod ERG ReductionOD OS 1/74/F AA 20/60 - 2 5/600 Central and peripheral loss 1 Gly1448Arg C = R 2/35/F W 10/350 5/400 Central and peripheral loss 1 Ala1038Val Leu541Pro C = R 3/42/F H 20/400 20/400 Central and peripheral loss 1 Ala1038Val Trp1618stop C = R 4/54/F W 10/180 10/140 Central scotoma 1 Donor splice, 5bp3Ј g-a intron 40 C = R 5/36/F W 10/120 10/60 - 1 Central scotoma 1 Leu541Pro Asp600Tyr C ↓ R 6/49/F W 5/160 5/180 Central and peripheral loss 1 Donor splice 5bp3Ј g-a intron 40 C = R 7/49/F W 10/350 4/350 Central and peripheral loss 1 Glu328Stop Val767Asp C = R 8/40/M W 10/225 20/400 Central and peripheral loss 1 Ala1038Val C = R 9/36/M W 5/600 5/350 Central and peripheral loss 1 Gly550Arg C = R 10/39/F AA 20/100 - 2 20/400 Central scotoma 1 Ala1038Val C = R 11/26/F W 20/200 20/200 Central and peripheral loss 1 Val2050Leu C ↓ R 12/36/M W 20/200 20/80+1 Central scotoma 1 Donor splice 5bp3Ј g-a intron 40 C = R 13/43/M AA 20/400 20/200 Central and peripheral loss 2 Leu1201Arg C = R (ND) 14/33/M P 20/40+1 20/50 Central scotoma 2 Leu2027Phe C ↓ R 15/44/M AA CF 20/400 Central and peripheral loss 2 Leu1201Arg C = R (ND) 16/56/M AA 20/40 20/40 Central scotoma 2 Leu2027Phe C = R Abbreviations: AA, African American; C ↓ R, cone responses more reduced than rod amplitudes; C = R, cone and rod amplitudes were similarly reduced; CF, counting fingers; ERG, electroretinogram; H, Hispanic; ND, nondetectable; P, Palestinian; W, white. Login to comment
60 Of the 12 patients with diffuse pigmentary changes (type 1), 4 harbored an Ala1038Val change, which is the second most common ABCA4 variant we have observed in patients with Stargardt disease.19 Two of these 4 patients were African American. Login to comment

[hide] The ABCA4 gene in autosomal recessive cone-rod dys... Am J Hum Genet. 2002 Dec;71(6):1480-2. Ducroq D, Rozet JM, Gerber S, Perrault I, Barbet D, Hanein S, Hakiki S, Dufier JL, Munnich A, Hamel C, Kaplan J
The ABCA4 gene in autosomal recessive cone-rod dystrophies.
Am J Hum Genet. 2002 Dec;71(6):1480-2., [PMID:12515255]

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30 Among these 13 patients, 2 were homozygotes (from two consanguineous families), 4 were compound heterozygotes, and 7 were Letters to the Editor 1481 Table 1 ABCA4 Mutations in Patients with CRD Patient ABCA4 ALLELE 1 ABCA4 ALLELE 2 OriginNucleotide Change Effect Nucleotide Change Effect 16 AAC 286 GAC N96D - - France 52 ATC 466 GTC I156V - - North Africa 57 ATC 466 GTC I156V GGG 1819 AGG G607R North Africa 51 CGA 455 CAA 5084ϩ1G/A R152Q Frameshift CGC 3323 TGC AGT 6764 ATT R1108C S2256I France 11 CGT 764 TGT R255C - - France 41 GCC 3113 GTC A1038V - - France 60 CTG 3602 CGG L1201R AGT 6764 ATT S2256I South Africa 21 CTC 5908 TTC L1970F - - France 30 AGT 6764 ATT S2256I - - Africa 48 GAA 3259 TAA E1087X - - France 2 2617 del CT Frameshift 2617 del CT Frameshift Portugal 5 571-2A/G Frameshift 571-2A/G Frameshift Morocco 61 CGG 4918 TGG R1602W GGC 5929 AGC G1977S England single heterozygotes (see table 1). Login to comment
31 Among these 13 patients, 2 were homozygotes (from two consanguineous families), 4 were compound heterozygotes, and 7 were Letters to the Editor 1481 Table 1 ABCA4 Mutations in Patients with CRD Patient ABCA4 ALLELE 1 ABCA4 ALLELE 2 Origin Nucleotide Change Effect Nucleotide Change Effect 16 AAC 286 GAC N96D - - France 52 ATC 466 GTC I156V - - North Africa 57 ATC 466 GTC I156V GGG 1819 AGG G607R North Africa 51 CGA 455 CAA 5084af9;1G/A R152Q Frameshift CGC 3323 TGC AGT 6764 ATT R1108C S2256I France 11 CGT 764 TGT R255C - - France 41 GCC 3113 GTC A1038V - - France 60 CTG 3602 CGG L1201R AGT 6764 ATT S2256I South Africa 21 CTC 5908 TTC L1970F - - France 30 AGT 6764 ATT S2256I - - Africa 48 GAA 3259 TAA E1087X - - France 2 2617 del CT Frameshift 2617 del CT Frameshift Portugal 5 571-2A/G Frameshift 571-2A/G Frameshift Morocco 61 CGG 4918 TGG R1602W GGC 5929 AGC G1977S England single heterozygotes (see table 1). Login to comment

[hide] Macular pigment and visual acuity in Stargardt mac... Graefes Arch Clin Exp Ophthalmol. 2002 Oct;240(10):802-9. Epub 2002 Sep 14. Zhang X, Hargitai J, Tammur J, Hutchinson A, Allikmets R, Chang S, Gouras P
Macular pigment and visual acuity in Stargardt macular dystrophy.
Graefes Arch Clin Exp Ophthalmol. 2002 Oct;240(10):802-9. Epub 2002 Sep 14., [PMID:12397427]

Abstract [show]
PURPOSE: To test the hypothesis that macular pigment reflects foveal cone function and possibly the presence of foveal cones in recessive Stargardt macular dystrophy. METHODS: Sixteen patients (32 eyes) diagnosed to have Stargardt macular dystrophy by clinical criteria were studied with a scanning laser ophthalmoscope (SLO) comparing argon laser blue (488 nm), green (514), helium-neon laser red (633 nm) and infrared diode laser (780 nm) images for the presence or absence of macular pigment in the fovea. Fifteen of the patients were screened for mutations in the ABCR gene. Eyes were graded into three categories: those without foveal macular pigment, those with partial pigment and those with normal amounts of macular pigment. These categories were compared with visual acuity determined by the Snellen chart. RESULTS: All patients with a visual acuity of 20/200 or worse had no macular pigment in the fovea. All patients with visual acuity of 20/40 or better had a normal amount of macular pigment in the fovea. Patients with partial macular pigment had intermediary acuity values except for two eyes, one with 20/20 and another with 20/200 acuity. Infrared light revealed more retinal abnormalities than blue light at early stages of the disease. CONCLUSION: Foveal macular pigment is related to foveal cone acuity in Stargardt macular dystrophy and may be a marker for the presence of foveal cones. Infrared light is a sensitive monitor of early Stargardt macular dystrophy.

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54 Blue light images (A, C); infrared images (B, D) Table 1 Visual acuity, macular pigment and ABCR mutations in patients with Stargardt dystrophy Patient Age/Sex Visual Acuity Macular Pigment Exon Allele 1 Exon Allele 2 OD OS OD OS 1 33F 0.67 0.38 + + ND ND 2 36F 1 0.5 + + ND ND 3 54F 0.48 0.6 + + 42 G1961E 42 G1061E 4 11M 0.8 1 + + NS NS 5 33F 0.67 0.4 +- + 20 V989A ND 6 12F 0.5 0.2 +- +- 30 C1490Y 40 GIVS+5A 7 47M 0.5 0.4 +- +- 17 G863A/R943Q 45 R2077W 8 53M 0.1 1 +- +- 14 W663X ND 9 29F 0.1 0.1 +- +- 26 3819insT ND 10 43M 0.005 0.005 - - 17 G863A/R943Q ND 11 32F 0.1 0.1 - - 19 N965S ND 12 29F 0.005 0.005 - - 23 R1129H ND 13 30F 0.1 0.1 - - 5 R152Q ND 14 63F 0.1 0.1 - - 42 G1961E ND 15 36M 0.07 0.1 - +- 13 Q636H 42 G1961E 16 41F 0.005 0.005 - - 12 L514P/A1038V ND NS: Not screened; ND: Not detected + Normal macular pigment; +- Partial macular pigment; - Absent macular pigment absorption of infrared light in the center of the macula where maximum absorption of blue light occurs, implying that the macula pigments in this subject`s foveas are normal. Login to comment

[hide] Phenotypes of 16 Stargardt macular dystrophy/fundu... Graefes Arch Clin Exp Ophthalmol. 2002 Aug;240(8):628-38. Epub 2002 Jul 4. Gerth C, Andrassi-Darida M, Bock M, Preising MN, Weber BH, Lorenz B
Phenotypes of 16 Stargardt macular dystrophy/fundus flavimaculatus patients with known ABCA4 mutations and evaluation of genotype-phenotype correlation.
Graefes Arch Clin Exp Ophthalmol. 2002 Aug;240(8):628-38. Epub 2002 Jul 4., [PMID:12192456]

Abstract [show]
PURPOSE: To determine the phenotypic variability in patients with compound heterozygous or homozygous ABCA4 mutations, and to correlate the phenotypes with the functional properties of the altered protein. METHODS: Sixteen patients from 13 families with signs of Stargardt macular dystrophy/fundus flavimaculatus and known mutations on both alleles of the ABCA4 gene (15 compound heterozygous, one homozygous) were characterized by clinical examination, fundus autofluorescence, psychophysics (color vision, kinetic and two-color dark- and light-adapted static threshold perimetry), and electrophysiology (Ganzfeld, multifocal ERG, EOG). RESULTS: The homozygous 5917delG mutation resulted in the earliest disease manifestation (at 5 years) and a general cone-rod dysfunction, whereas the compound heterozygous mother (5917delG, G1961E) exhibited a very mild phenotype. Compound heterozygotes for the IVS40+5G-->A and the C1488Y or Y362X mutation showed also an early age of onset but only a central dysfunction. The effect of the 2588G-->C mutation, the G1961E mutation, and the complex mutation L541P-A1038V depended on the mutation in the second allele. Genotype-phenotype correlation appeared possible in most instances. Psychophysics revealed a simultaneous yet not necessarily congruent cone and rod dysfunction. CONCLUSIONS: The type and combination of ABCA4 mutations in compound heterozygous patients determined were compatible with the severity of the phenotype as to age of onset and the functional consequences in the majority of patients. Unexplained phenotypic differences indicate the influence of other factors. ABCA4 mutations result in cone and rod dysfunction. Different disease durations limit the power of presently available genotype-phenotype correlations.

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4 The effect of the 2588G→C mutation, the G1961E mutation, and the complex mutation L541P-A1038V depended on the mutation in the second allele. Login to comment
81 Patient 2 had a Table 2 Identified mutations in the ABCR alleles in the 16 patients (ND not tested) Patient ABCA4 allele 1 ABCA4 allele 2 no./sex (1*) Nucleotide changes Effects Nucleotide changes Effects 1a/F (139) 5917delG Frameshift 5917delG Frameshift 1b/F(139b) 5917delG Frameshift 5882G→A G1961E 2/M (167) IVS 40+5G→A Splice 4463G→A C1488Y 3/F (108) IVS 40+5G→A Splice 1086T→A Y362X 4/M (109) 1622T→C- L541P-A1038V 2564G→A W855X 3113C→T 5/F (113) 1622T→C- L541P-A1038V 2588G→C Splice 3113C→T 6/M (50) 2588G→C Splice 3113C→T A1038V 7b/M (138) 2588G→C Splice IVS13+1G→A Splice 7a/F Not tested Splice Not tested Splice 8/F (111) 5882G→A G1961E 2292delT-2295T→G Frameshift-S765R 9/F (147) 5882G→A G1961E IVS36+1G→A Splice 10/F (41) 5882G→A G1961E 2041C→T R681X 11a/F (114) 5882G→A G1961E 6609C→A Y2203X 11b/M ND ND 12/F (148) 3292C→T R1097C 6609C→A Y2203X 13/M (107) 3528insTGCA Frameshift 2291G→A C764Y* Refers to the patients` ID in [42] Table3Demographicdataandclinicalfeaturesofthe16patients(NDtestnotdone,Aabnormal,Nnormal,RreducedArdenratio,NRnotreliable,NAmfERGnotanalyz- able,+present,-absent,DCdarkchoroid,DDdiscdiameter) Pat.aAgeDiseaseVisualacuityColorFun-GanzfeldERGEOGmfERGStatictwo-colorKineticperimetryAngio-FundusAF atdurationvisiondusbthresholdperimetrygraphy onset/(years)ODOSRodMaximalConePeakResponseCentralCon-CentralCircularPeri- examresponseresponseresponsetimesdensitiesMeanRSLMeanCSLscotomacentricAFAFmacular/ b-wavecb-wavec30Hzab-abnormalc(dB)e(dB)efortargetcon-AF flickerdnormaldstriction <=13°>13°<=13°>13° 1a5/10520/250*20/250NDIfNDNANAND-ND-NRNRND+-- 1b32/32020/30*20/30NDINDNNNDN5-10°ND-ND-NDNDND+-- 27/15820/10020/200*AIINNNND5-15°5-25°2120--ND+-+ 39/13420/250*20/250AIINNNN5-15°5-25°0030I-2e-ND+++ 47/12520/25020/250*AIIINNNN5-25°5-25°ND-ND-I-4e-ND>1DD-- 520/4525<20/400<20/400*AIIINNNNNANA194143II-3e+ND>1DD-+ 614/19520/200*20/200AIINDNNNR5-10°5-25°1080I-4e-ND+-+ 7b16/23720/25020/250*AIINDNNR20°5-25°101113I-3e-ND+-+ 7a6/272120/20020/200NDIINDNDNDNDND-ND-ND-NDNDNDND 815/18320/100*20/100AINNND5-10°5-25°2010I-2e-N++- 921/23220/40*20/200AINDNNN10-15°5°0060NDNDN+++ 1024/31720/400*20/400AIINNNN5°5-15°3270I-2e-ND+-+ 11a16/331720/200*20/200AIINDNNNN5-15°81140I-2e-NDND 11b26/28220/20020/200*AINNNN5-10°,5-10°0010I-2e-ND+++ 20-25° 1238/571920/22*20/250NDIII(OD)ND5-25°5-25°35/3835/39ND-III/4e-NDND 1314/16220/100*20/100AIINDNNNN5-25°1120ND-DC+-+ aOnenumberindicatesonefamily bReferredtoTable1 cResults<5thpercentile dResults>95thpercentile eRSL(rodsensitivityloss;500nm,darkadapted)andCSL(conesensitivityloss; 600nm,lightadapted)comparedtothe10thpercentileofnormals;mfERGrespons- eswereanalyzedforallbutthecentral(1°inradius)responseduetohighnoise fRetinalvesselattenuation *EyetestedformfERG/staticperimetry CSL within 13° and a more widespread RSL over the 30° test field. Login to comment
84 Patients with the complex mutation L541P-A1038V Two patients were compound heterozygous for this complex mutation and a nonsense mutation (W855X, patient 4) as well as a mutation with bipartite outcome [2588G→C (G863A/G863del), patient 5]. Login to comment
91 Patients with the missense mutation 2588G→C Four patients were compound heterozygous for this missense mutation and an alteration in the donor splice site of exon 13 (IVS13+1G→A, siblings 7a and 7b), a complex mutation [L541P-A1038V (patient 5, results described above)] or a missense mutation (A1038V, patient 6). Login to comment
158 The slightly more advanced cone dysfunction in patient 3 could be caused by the more severe functional restrictions of the associated nonsense mutation (Y362X), which results in a non-functional gene product. Login to comment
159 The complex mutation L541P-A1038V was associated with an earlier onset and more rapid progression when occurring together with the W855X nonsense mutation (patient 4) than with the missense mutation 2588G→C (patient 5). Login to comment
160 Both mutations on their own, L541P and A1038V, have been associated with severely reduced but not abolished ATPase activity [49]. Login to comment
164 The missense mutation 2588G→C resulted in a more advanced cone and rod dysfunction when associated with the IVS13+1G→A splice site (siblings 7a and 7b) than with the missense mutation A1038V (patient 6) in the second allele. Login to comment
165 This difference is predictable since the A1038V showed a reduced ATPase activity of about 60% but a nearly wild-type-like yield [49]. Login to comment
163 The missense mutation 2588G࢐C resulted in a more advanced cone and rod dysfunction when associated with the IVS13+1G࢐A splice site (siblings 7a and 7b) than with the missense mutation A1038V (patient 6) in the second allele. Login to comment

[hide] Alterations of slow and fast rod ERG signals in pa... Invest Ophthalmol Vis Sci. 2002 Apr;43(4):1248-56. Scholl HP, Besch D, Vonthein R, Weber BH, Apfelstedt-Sylla E
Alterations of slow and fast rod ERG signals in patients with molecularly confirmed Stargardt disease type 1.
Invest Ophthalmol Vis Sci. 2002 Apr;43(4):1248-56., [PMID:11923272]

Abstract [show]
PURPOSE: To investigate the slow and fast rod signals of the scotopic 15-Hz flicker ERG in patients with molecularly confirmed Stargardt disease type I (STGD1). There is evidence that these slow and the fast rod ERG signals can be attributed to the rod bipolar-AII cell pathway and the rod-cone coupling pathway, respectively. METHODS: Twenty-seven patients with STGD1 with mutations in both alleles of the ABCA4 gene were included. Scotopic ERG response amplitudes and phases to flicker intensities ranging from -3.37 to -0.57 log scotopic troland x sec (log scot td x sec) were measured at a flicker frequency of 15 Hz. In addition, scotopic standard ERGs were obtained. Twenty-two normal subjects served as controls. RESULTS: The amplitudes of both the slow and fast rod ERG signals were significantly reduced in the STGD1 group. The phases of the slow rod signals lagged significantly, whereas those of the fast rod signals did not. The standard scotopic ERG did not reveal significant alterations. CONCLUSIONS: The results provide evidence that a defective ABCA4 transporter can functionally affect both the rod bipolar-AII cell pathway and the rod-cone coupling pathway. In STGD1, the scotopic 15-Hz flicker ERG may reveal subtle abnormalities at different sites within the rod system that remain undetected by standard ERG techniques.

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97 Characteristics of the 27 patients with STGD1 Patient Sex Age Onset VA (OD) VA (OS) CFC DF Mut(1) Mut(2) Slow Rod ERG Fast Rod ERG 1 M 32 9 1/50 20/400 Severe ϩϩ Q1412X R2077W 19.2 12.1 2 M 49 17 20/200 20/200 Severe ϩ 768G3T G1961E 56.1 23.8 3 M 46 30 20/40 20/200 Mild ϩ E471K G1961E 31.7 29.0 4* M 27 19 20/32 20/100 Moderate ϩ 2588G3C E1885K 35.0 45.1 5* M 31 18 20/400 20/400 Severe ϩϩ 2588G3C E1885K 36.1 39.1 6* F 29 12 20/200 20/200 Moderate ϩϩ 2588G3C E1885K 23.4 8.1 7 F 23 18 20/400 20/400 Mild ϩϩ E1399K G1977S 103.5 39.3 8 M 28 17 20/200 20/200 Mild ϩϩ R1898H G1975R 44.4 19.5 9 M 39 29 20/100 20/200 Moderate ϩ G607R G1961E 45.8 20.7 10 F 23 17 20/200 20/200 Mild - P68L S1689P 80.2 25.9 11 F 33 30 20/50 20/50 Mild - E1399K G1961E 49.8 62.0 12 M 50 42 20/400 20/64 Severe ϩϩ 2588G3C L541P/A1038V 53.8 30.2 13 M 36 25 20/40 20/32 Moderate ϩϩ 296insA A1038V 88.2 40.0 14 F 55 16 HM HM Severe ϩϩ Q635K IVS40ϩ5G3A 11.7 11.2 15 F 27 25 20/100 20/50 Moderate ϩ 2588G3C Q1412X 65.8 71.5 16 F 45 14 1/50 1/35 Severe ϩϩ L541P/A1038V S1063P 16.4 16.6 17 M 40 23 20/100 20/200 Moderate ϩ 296insA G1961E 46.1 58.3 18** M 35 15 20/400 20/400 Moderate ϩ 2588G3C Q1750X 14.1 12.9 19** M 43 14 HM HM Severe ϩϩ 2588G3C Q1750X 17.4 8.6 20 F 32 8 20/200 20/200 Severe ϩ G1961E G1961E 66.2 79.0 21 F 23 12 20/400 20/400 Mild - R212C T9591 24.6 25.3 22 F 29 9 20/200 20/200 Moderate ϩ L541P/A1038V G1961E 72.3 31.8 23 M 20 9 20/400 20/400 Moderate ϩϩ L541P/A1038V IVS40ϩ;5G3A 64.7 42.2 24 F 39 23 20/400 20/50 Moderate - W663X G1961E 92.6 68.8 25 F 41 36 20/200 20/64 Severe ϩ F1440V G1748R 97.2 52.7 26*** M 13 10 20/100 20/200 Moderate - R572Q/2588G3C IVS35ϩ2T3A 59.2 33.5 27*** M 16 15 20/200 20/200 Moderate ϩ R572Q/2588G3C IVS35ϩ2T3A 31.1 22.9 Age at examination (y), gender, age of onset (y), visual acuity (VA), central fundus changes (CFC), and existence and distribution of the typical white-yellow flecks (DF) are shown. Login to comment

[hide] Differential occurrence of mutations causative of ... Hum Mutat. 2002 Mar;19(3):189-208. Pang CP, Lam DS
Differential occurrence of mutations causative of eye diseases in the Chinese population.
Hum Mutat. 2002 Mar;19(3):189-208., [PMID:11857735]

Abstract [show]
Ethnic differences and geographic variations affect the frequencies and nature of human mutations. In the literature, descriptions of causative mutations of eye diseases in the Chinese population are few. In this paper we attempt to reveal molecular information on genetic eye diseases involving Chinese patients from published and unpublished works by us and other groups. Our studies on candidate genes of eye diseases in the Chinese population in Hong Kong include MYOC and TISR for primary open angle glaucoma, RHO and RP1 for retinitis pigmentosa, ABCA4 and APOE for age-related macular degeneration, RB1 for retinoblastoma, APC for familial adenomatous polyposis with congenital hypertrophy of retinal pigment epithelium, BIGH3/TGFBI for corneal dystrophies, PAX6 for aniridia and Reiger syndrome, CRYAA and CRYBB2 for cataracts, and mtDNA for Leber hereditary optic neuropathy. We have revealed novel mutations in most of these genes, and in RHO, RP1, RB1, BIGH3, and PAX6 we have reported mutations that contribute to better understanding of the functions and properties of the respective gene products. We showed absence of MYOC does not necessarily cause glaucoma. No disease causative mutations have been identified in MYOC or ABCA4. There are similarities in the patterns of sequence alterations and phenotype-genotype associations in comparison with other ethnic groups, while the MYOC, RB1, APC, and PAX6 genes have more Chinese-specific sequence alterations. Establishment of a mutation database specific for the Chinese is essential for identification of genetic markers with diagnostic, prognostic, or pharmacological values.

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162 G1961E, G863A/delG863, and A1038V together account for about 10% of ABCA4 mutations in Caucasians. Login to comment
165 About 20% of them have G1961E and 10% G2588C, while the L541P-A1038V complex allele appears to be a founder mutation [Rivera et al., 2000]. Login to comment

[hide] Mechanistic studies of ABCR, the ABC transporter i... J Bioenerg Biomembr. 2001 Dec;33(6):523-30. Sun H, Nathans J
Mechanistic studies of ABCR, the ABC transporter in photoreceptor outer segments responsible for autosomal recessive Stargardt disease.
J Bioenerg Biomembr. 2001 Dec;33(6):523-30., [PMID:11804194]

Abstract [show]
ABCR is an ABC transporter that is found exclusively in vertebrate photoreceptor outer segments. Mutations in the human ABCR gene are responsible for autosomal recessive Stargardt disease, the most common cause of early onset macular degeneration. In this paper we review our recent work with purified and reconstituted ABCR derived from bovine retina and from cultured cells expressing wild type or site-directed mutants of human ABCR. These experiments implicate all-trans-retinal (or Schiff base adducts between all-trans-retinal and phosphatidylethanolamine) as the transport substrate, and they reveal asymmetric roles for the two nucleotide binding domains in the transport reaction. A model for the retinal transport reaction is presented which accounts for these experimental observations.

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99 Among the variants tested in NBD-1, T971N and A1038V have a lower 528 Sun and Nathans Fig. 4. Login to comment
110 The complete or nearly complete elimination of all ATPase activity produced by single NBD mutations-T971N, A1038V, or L1971R-implies that the two NBDs are allosterically coupled. Login to comment

[hide] Cosegregation and functional analysis of mutant AB... Hum Mol Genet. 2001 Nov 1;10(23):2671-8. Shroyer NF, Lewis RA, Yatsenko AN, Wensel TG, Lupski JR
Cosegregation and functional analysis of mutant ABCR (ABCA4) alleles in families that manifest both Stargardt disease and age-related macular degeneration.
Hum Mol Genet. 2001 Nov 1;10(23):2671-8., [PMID:11726554]

Abstract [show]
Mutations in ABCR (ABCA4) have been reported to cause a spectrum of autosomal recessively inherited retinopathies, including Stargardt disease (STGD), cone-rod dystrophy and retinitis pigmentosa. Individuals heterozygous for ABCR mutations may be predisposed to develop the multifactorial disorder age-related macular degeneration (AMD). We hypothesized that some carriers of STGD alleles have an increased risk to develop AMD. We tested this hypothesis in a cohort of families that manifest both STGD and AMD. With a direct-sequencing mutation detection strategy, we found that AMD-affected relatives of STGD patients are more likely to be carriers of pathogenic STGD alleles than predicted based on chance alone. We further investigated the role of AMD-associated ABCR mutations by testing for expression and ATP-binding defects in an in vitro biochemical assay. We found that mutations associated with AMD have a range of assayable defects ranging from no detectable defect to apparent null alleles. Of the 21 missense ABCR mutations reported in patients with AMD, 16 (76%) show abnormalities in protein expression, ATP-binding or ATPase activity. We infer that carrier relatives of STGD patients are predisposed to develop AMD.

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97 Pedigree Maternal allele Paternal allele AMD relative A priori Cosegregation AR19 pGM, -6 0.5 - AR33 [W1408R; R1640W] R24H and D1532N mA, -16 0.5 Yes AR59 4232insTATG C1488R pGM, -6 0.5 No AR80 T1526M pGF, -5 0.5 - AR80 T1526M mGF, -7 0.5 Yes AR125 4947delC C1488R pGM, -7 0.5 Yes AR215 [H1406Y; V2050L] pGM, -5 0.5 - AR218 2160+1G→C G1961E mA, -8 0.5 No AR262 W821R pGGF, -7 0.25 No AR271 P68R E1087K mGA, -6 0.25 No AR335 D645N F608I mGM, -9 0.5 Yes AR382 R1108C mGM, -6 0.5 Yes AR389 E2096K 5714+5G→A pGM, -8 0.5 Yes AR397 5196+1G→A 5585-1G→A mA, -5 0.5 No AR410 A1038V 768G→T pC, -5 0.25 Yes AR422 pGM, -6 0.5 - AR423 P1380L D1532N pGF, -4 0.5 No AR468 P1380L P1380L mU, -9 0.5 Yes AR484 L2027F G550R mGU, -5 0.25 Yes AR562 R2107H 3050+5G→A pGU, -5 0.25 No AR643 5196+2T→C L2027F mU, -4 0.5 Yes AR661 P1380L C54Y mGF, -6 0.5 Yes AR669 664del13 pGF, -4 0.5 No AR534 W821R P1380L pGM, -7 0.5 Yes (17) Family 1 R212C I2113M mGM, I-2 0.5 Yes (27) Family 2 R1108C R2107H mGM, I-2 0.5 Yes (27) Family 3 R212C G1977S mGF, I-1 0.5 Yes (27) 10.25 15 unlikely to account for many of the remaining alleles (our unpublished observations). Login to comment
114 Sun et al. (28) reported substantial defects in protein expression or ATP binding of eight AMD-associated mutations (R212C, G863A, A1038V, R1108C, R1129L, P1380L, G1961E and L2027F) and an abnormal increase in the ATPase activity of the D2177N mutation, and they reported mild defects or wild-type activity within the sensitivity of the assay in four other AMD-associated variants (E471K, C1488R, T1526M and R1898H). Login to comment

[hide] Mutational scanning of the ABCR gene with double-g... Hum Genet. 2001 Sep;109(3):326-38. Fumagalli A, Ferrari M, Soriani N, Gessi A, Foglieni B, Martina E, Manitto MP, Brancato R, Dean M, Allikmets R, Cremonesi L
Mutational scanning of the ABCR gene with double-gradient denaturing-gradient gel electrophoresis (DG-DGGE) in Italian Stargardt disease patients.
Hum Genet. 2001 Sep;109(3):326-38., [PMID:11702214]

Abstract [show]
Mutations in the retina-specific ABC transporter (ABCR) gene are responsible for autosomal recessive Stargardt disease (arSTGD). Mutation detection efficiency in ABCR in arSTGD patients ranges between 30% and 66% in previously published studies, because of high allelic heterogeneity and technical limitations of the employed methods. Conditions were developed to screen the ABCR gene by double-gradient denaturing-gradient gel electrophoresis. The efficacy of this method was evaluated by analysis of DNA samples with previously characterized ABCR mutations. This approach was applied to mutation detection in 44 Italian arSTGD patients corresponding to 36 independent genomes, in order to assess the nature and frequency of the ABCR mutations in this ethnic group. In 34 of 36 (94.4%) STGD patients, 37 sequence changes were identified, including 26 missense, six frameshift, three splicing, and two nonsense variations. Among these, 20 had not been previously described. Several polymorphisms were detected in affected individuals and in matched controls. Our findings extend the spectrum of mutations identified in STGD patients and suggest the existence of a subset of molecular defects specific to the Italian population. The identification of at least two disease-associated mutations in four healthy control individuals indicates a higher than expected carrier frequency of variant ABCR alleles in the general population. Genotype-phenotype analysis in our series showed a possible correlation between the nature and location of some mutations and specific ophthalmoscopic features of STGD disease.

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37 DNA samples (n=22) carrying previously identified mutations in the ABCR gene were employed as controls for evaluating the efficacy of the DG-DGGE approach in detecting sequence variations R572Q (Lewis et al. 1999), Y639X (Lewis et al. 1999), G863A (Lewis et al. 1999; Maugeri et al. 1999), A1038V (Rozet et al. 1998), T1019M (Rozet et al. 1998), 3211insGT (Lewis et al. 1999), P1380L (Lewis et al. 1999), H1406Y (Lewis et al. 1999), 4947delC (Lewis et al. 1999), H1838Y (Lewis et al. 1999), 5714+5G→A (Cremers et al. 1998), N1868I (De La Paz et al. 1999), L1938L (Rivera et al. 2000), G1961E (Allikmets et al. 1997a, 1997b), L1970F (Lewis et al. 1999), L2027F (Nasonkin et al. 1998), V2050L (Lewis et al. 1999), E2131K (Lewis et al. 1999), R2139W (Lewis et al. 1999), 6709insG (Lewis et al. 1999), D2177N (Allikmets et al. 1997a, 1997b), 2181del12 (Lewis et al. 1999). Login to comment

[hide] Mutations in ABCR (ABCA4) in patients with Stargar... Invest Ophthalmol Vis Sci. 2001 Sep;42(10):2229-36. Briggs CE, Rucinski D, Rosenfeld PJ, Hirose T, Berson EL, Dryja TP
Mutations in ABCR (ABCA4) in patients with Stargardt macular degeneration or cone-rod degeneration.
Invest Ophthalmol Vis Sci. 2001 Sep;42(10):2229-36., [PMID:11527935]

Abstract [show]
PURPOSE: To determine the spectrum of ABCR mutations associated with Stargardt macular degeneration and cone-rod degeneration (CRD). METHODS: One hundred eighteen unrelated patients with recessive Stargardt macular degeneration and eight with recessive CRD were screened for mutations in ABCR (ABCA4) by single-strand conformation polymorphism analysis. Variants were characterized by direct genomic sequencing. Segregation analysis was performed on the families of 20 patients in whom at least two or more likely pathogenic sequence changes were identified. RESULTS: The authors found 77 sequence changes likely to be pathogenic: 21 null mutations (15 novel), 55 missense changes (26 novel), and one deletion of a consensus glycosylation site (also novel). Fifty-two patients with Stargardt macular degeneration (44% of those screened) and five with CRD each had two of these sequence changes or were homozygous for one of them. Segregation analyses in the families of 19 of these patients were informative and revealed that the index cases and all available affected siblings were compound heterozygotes or homozygotes. The authors found one instance of an apparently de novo mutation, Ile824Thr, in a patient. Thirty-seven (31%) of the 118 patients with Stargardt disease and one with CRD had only one likely pathogenic sequence change. Twenty-nine patients with Stargardt disease (25%) and two with CRD had no identified sequence changes. CONCLUSIONS: This report of 42 novel mutations brings the growing number of identified likely pathogenic sequence changes in ABCR to approximately 250.

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68 A rarely encountered missense change, Ala1637Thr, was interpreted as nonpathogenic because it was found in a patient (032-066) who also had two obviously null mutations determined to be allelic by segregation analysis, Lys356Ter and Gln1513(insC). Login to comment
69 Another change, Ala1038Val, was found in two patients (032-023 and 034-035), and in both cases segregation analysis showed that it was in cis with Leu541Pro, a combination also reported by Rivera et al.23 We interpreted Leu541Pro as pathogenic because it was found without the Ala1038Val change more frequently in patients than in control subjects. Login to comment
70 However, Sun et al.26 have shown abnormal ABCR function associated with either Ala1038Val or Leu541Pro, and it is therefore possible that both these changes are pathogenic in isolation. Login to comment
89 ABCR Sequence Changes Found in 118 Patients with Stargardt and 8 with CRD Patient ID Mutations (Amino Acid Based) Sequence Change (Nucleotide Based) Het/Hom Other Sequence Changes 21 Null Mutations 071-004 Met1Val ATG 3 GTC Het None 035-002* Ser84(insCAAA)30 251ins4 Het IVS36 ϩ 1G 3 A 034-039 Ser84(insCAAA)30 251ins4 Het Gly1961Glu 032-018 Arg152Ter23 CGA 3 TGA Het Arg2107Cys 032-005 Ala222(del13bp) 666del13 [AAAGACGGTGCGC] Het None 032-039 Ala222(del13bp) 666del13 [AAAGACGGTGCGC] Het None 032-060 [Ser278(delT); Arg1300Gln] [832delT; CGA 3 CAA] Het Pro1486Leu 032-066* Lys356Ter AAG 3 TAG Het Gln1513(insC) 032-072 - IVS13 ϩ 2T 3 C Het Val77Glu 032-073 Arg681Ter21 CGA 3 TGA Het Leu1388Pro 034-016 Ser1071(insGT)31 3212insGT Het None 032-065 Ser1071(insGT)31 3212insGT Het None 035-003 Ile1114(delC)5 3340delC Het Pro1380Leu 007-014* - IVS26 ϩ 1G 3 A Het Asn1345(insCA) 007-014* Asn1345(insCA) 4034insCA Het IVS26 ϩ 1G 3 A 032-066* Gln1513(insC) 4538insC Het Lys356Ter 032-010 Gln1513(insC) 4538insC Het None 032-024 Pro1570(delC)16 4710delC Het Gly1961Glu 032-016 Thr1721 (delAC) delete AC @ nt 5161 Het Thr1525Met 035-002* - IVS36 ϩ 1G 3 A23 Het Ser84(insCAAA) 034-031 Leu1741(del11) 5194del11 [GTGGTGGGCAT] Het Gly1961Glu 032-051 Trp1772Ter TGG 3 TGA Het None 032-022 - IVS41-2delA Het Gly1961Glu 032-081* Val1973(delG) 5917delG Hom None 034-017 Gly2100(delG) 6300delG Het Gly1961Glu 55 Missense and One In-Frame Deletion 032-020 Cys54Tyr15 TGC 3 TAC Het Gly863Ala 035-012 Cys54Tyr15 TGC 3 TAC Het Arg1108Cys 071-007 Cys54Tyr15 TGC 3 TAC Het Val935Ala 071-003 Asn58Lys AAC 3 AAG Het Leu1201Arg 032-069 Ala60Val15 GCG 3 GTG Het None 032-028 Gly65Glu16 GGA 3 GAA Het None 032-072 Val77Glu GTG 3 CAG Het IVS13 ϩ 2T 3 C 034-013 Gln190His CAG 3 CAC Het Gly1961Glu 032-076 Leu244Pro CTG 3 CCG Hom None 032-012 Pro309Arg CCA 3 CGA Het Arg1300Gln 032-054 Phe525Cys TTT 3 TGT Het Ile1846Thr 032-046 Arg537Cys CGT 3 TGT Het Val989Ala 034-038 Arg537Cys CGT 3 TGT Het Gly863Ala 032-095 Leu541Pro18 CTA 3 CCA Het None 034-022 Leu541Pro18 CTA 3 CCA Het Leu2027Phe 035-001 Leu541Pro18 CTA 3 CCA Het None 032-009 Leu541Pro18 CTA 3 CCA Het None 032-023 [Leu541Pro18 ; Ala1038Val27 ] [CTA 3 CCA; GCC 3 GTC] Het Gly863Ala 034-035 [Leu541Pro18 ; Ala1038Val27 ] [CTA 3 CCA; GCC 3 GTC] Het Gly863Ala 032-011 Ala549Pro GCC 3 CCC Het Gly1961Glu 032-044 Gly550Arg GGA 3 AGA Het None 032-085 Arg602Gln CGG 3 CAG Het Val643Met 032-090 Gly607Arg GGG 3 AGG Het Leu2027Phe 032-085 Val643Met GTG 3 ATG Het Arg602Gln 032-042 Val767Asp30 GTC 3 GAG Het Pro1486Leu 071-006 Val767Asp30 GTC 3 GAG Het Ile1562Thr 032-014 Leu797Pro CTG 3 CCG Het Pro1486Leu 032-038 Trp821Arg18 TGG 3 AGG Het None 034-045 Ile824Thr ATC 3 ACC Het Gly1961Glu 032-056 Gly863Ala5 GGA 3 GCA Het None 032-091 Gly863Ala5 GGA 3 GCA Het None 032-020 Gly863Ala5 GGA 3 GCA Het Cys54Tyr 032-023 Gly863Ala5 GGA 3 GCA Het [Leu541Pro; Ala1038Val] 034-011 Gly863Ala5 GGA 3 GCA Het Cys1488Arg 034-015 Gly863Ala5 GGA 3 GCA Het Thr1525Met 034-035 Gly863Ala5 GGA 3 GCA Het [Leu541Pro; Ala1038Val] 034-036 Gly863Ala5 GGA 3 GCA Het Cys2150Arg 034-038 Gly863Ala5 GGA 3 GCA Het Arg537Cys 071-007 Val935Ala GTA 3 GCA Het Cys54Tyr 032-043 Arg943Trp CGG 3 TGG Het Arg1108Leu 032-046 Val989Ala GTT 3 GCT Het Arg537Cys 071-005 Arg1108Cys18 CGC 3 TGC Het None Patient ID Mutations (Amino Acid Based) Sequence Change (Nucleotide Based) Het/Hom Other Sequence Changes 035-012 Arg1108Cys18 CGC 3 TGC Het Cys54Tyr 032-043 Arg1108Leu5 CGC 3 CTC Het Arg943Trp 032-097 Glu1122Lys18 GAG 3 AAG Het None 035-019 Glu1122Lys18 GAG 3 AAG Het None 071-003 Leu1201Arg15 CTG 3 CGG Het Asn58Lys 032-012 Arg1300Gln CGA 3 CAA Het Pro309Arg 032-068 Arg1300Gln CGA 3 CAA Het None 032-013 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 032-015 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 032-027 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 071-001 Pro1380Leu15 CCG 3 CTG Hom None 034-020 Pro1380Leu15 CCG 3 CTG Het Leu2027Phe 034-028 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 034-044 Pro1380Leu15 CCG 3 CTG Het Leu2027Phe 034-048 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 035-003 Pro1380Leu15 CCG 3 CTG Het Ile1114(delC) 032-073 Leu1388Pro CTG 3 CCG Het Arg681Ter 034-040 Trp1408Arg15 TGG 3 CGG Het Arg1640Trp 035-013 Trp1408Arg15 TGG 3 CGG Het Arg1640Trp 032-060 Pro1486Leu20 CCA 3 CTA Het [Ser278(delT); Arg1300Gln] 032-014 Pro1486Leu20 CCA 3 CTA Het Leu797Pro 032-025 Pro1486Leu20 CCA 3 CTA Het Asp1531Asn 032-042 Pro1486Leu20 CCA 3 CTA Het Val767Asp 034-011 Cys1488Arg15 TGC 3 CGC Het Gly863Ala 032-034 Cys1490Tyr15 TGC 3 TAC Het Ile1846Thr 032-084 Thr1525Met15 ACG 3 ATG Het Arg2139Trp 032-016 Thr1525Met15 ACG 3 ATG Het Thr1721(delAC) 032-021 Thr1525Met15 ACG 3 ATG Het None 032-041 Thr1525Met15 ACG 3 ATG Het None 034-015 Thr1525Met15 ACG 3 ATG Het Gly863Ala 032-049 Asp1531Asn15 GAC 3 AAC Het Gly1961Glu 034-019 Asp1531Asn15 GAC 3 AAC Het None 032-025 Asp1531Asn15 GAC 3 AAC Het Pro1846Leu 071-006 Ile1562Thr27 ATT 3 ACT Het Val767Asp 034-040 Arg1640Trp18 CGG 3 TGG Het Trp1408Arg 035-013 Arg1640Trp18 CGG 3 TGG Het Trp1408Arg 032-030* Arg1640Gln CGG 3 CAG Hom None 032-019 Pro1776Leu CCC 3 CTC Het Gly1961Glu 032-034 Ile1846Thr21 ATT 3 ACT Het Cys1490Tyr 032-054 Ile1846Thr21 ATT 3 ACT Het Phe525Cys 032-011 Gly1961Glu27 GGA 3 GAA Het Ala549Pro 032-013 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-015 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-019 Gly1961Glu27 GGA 3 GAA Het Pro1776Leu 032-022 Gly1961Glu27 GGA 3 GAA Het IVS41-2delA 032-024 Gly1961Glu27 GGA 3 GAA Het Pro1570(delC) 032-027 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-040 Gly1961Glu27 GGA 3 GAA Het None 032-049 Gly1961Glu27 GGA 3 GAA Het Asp1531Asn 034-013 Gly1961Glu27 GGA 3 GAA Het Gln190His 034-017 Gly1961Glu27 GGA 3 GAA Het Gly2100(delG) 034-021 Gly1961Glu27 GGA 3 GAA Het None 034-025 Gly1961Glu27 GGA 3 GAA Het None 034-028 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 034-031 Gly1961Glu27 GGA 3 GAA Het Leu1741(del11) 034-033 Gly1961Glu27 GGA 3 GAA Het None 034-039 Gly1961Glu27 GGA 3 GAA Het Ser84(insCAAA) 032-050 Gly1961Glu27 GGA 3 GAA Het None 034-045 Gly1961Glu27 GGA 3 GAA Het Ile824Thr 034-048 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-003 Gly1977Ser15 GGC 3 AGC Het Leu2027Phe 032-003 Leu2027Phe5 CTC 3 TTC Het Gly1977Ser 032-090 Leu2027Phe5 CTC 3 TTC Het Gly607Arg 034-006 Leu2027Phe5 CTC 3 TTC Het None 034-020 Leu2027Phe5 CTC 3 TTC Het Pro1380Leu 034-022 Leu2027Phe5 CTC 3 TTC Het Leu541Pro 034-044 Leu2027Phe5 CTC 3 TTC Het Pro1380Leu 035-011 Leu2027Phe5 CTC 3 TTC Het None 032-063 Arg2030Gln15 CGA 3 CAA Het None 032-093 Arg2030Gln15 CGA 3 CAA Het None 2232 Briggs et al. IOVS, September 2001, Vol. 42, No. Login to comment
88 ABCR Sequence Changes Found in 118 Patients with Stargardt and 8 with CRD Patient ID Mutations (Amino Acid Based) Sequence Change (Nucleotide Based) Het/Hom Other Sequence Changes 21 Null Mutations 071-004 Met1Val ATG 3 GTC Het None 035-002* Ser84(insCAAA)30 251ins4 Het IVS36 af9; 1G 3 A 034-039 Ser84(insCAAA)30 251ins4 Het Gly1961Glu 032-018 Arg152Ter23 CGA 3 TGA Het Arg2107Cys 032-005 Ala222(del13bp) 666del13 [AAAGACGGTGCGC] Het None 032-039 Ala222(del13bp) 666del13 [AAAGACGGTGCGC] Het None 032-060 [Ser278(delT); Arg1300Gln] [832delT; CGA 3 CAA] Het Pro1486Leu 032-066* Lys356Ter AAG 3 TAG Het Gln1513(insC) 032-072 - IVS13 af9; 2T 3 C Het Val77Glu 032-073 Arg681Ter21 CGA 3 TGA Het Leu1388Pro 034-016 Ser1071(insGT)31 3212insGT Het None 032-065 Ser1071(insGT)31 3212insGT Het None 035-003 Ile1114(delC)5 3340delC Het Pro1380Leu 007-014* - IVS26 af9; 1G 3 A Het Asn1345(insCA) 007-014* Asn1345(insCA) 4034insCA Het IVS26 af9; 1G 3 A 032-066* Gln1513(insC) 4538insC Het Lys356Ter 032-010 Gln1513(insC) 4538insC Het None 032-024 Pro1570(delC)16 4710delC Het Gly1961Glu 032-016 Thr1721 (delAC) delete AC @ nt 5161 Het Thr1525Met 035-002* - IVS36 af9; 1G 3 A23 Het Ser84(insCAAA) 034-031 Leu1741(del11) 5194del11 [GTGGTGGGCAT] Het Gly1961Glu 032-051 Trp1772Ter TGG 3 TGA Het None 032-022 - IVS41-2delA Het Gly1961Glu 032-081* Val1973(delG) 5917delG Hom None 034-017 Gly2100(delG) 6300delG Het Gly1961Glu 55 Missense and One In-Frame Deletion 032-020 Cys54Tyr15 TGC 3 TAC Het Gly863Ala 035-012 Cys54Tyr15 TGC 3 TAC Het Arg1108Cys 071-007 Cys54Tyr15 TGC 3 TAC Het Val935Ala 071-003 Asn58Lys AAC 3 AAG Het Leu1201Arg 032-069 Ala60Val15 GCG 3 GTG Het None 032-028 Gly65Glu16 GGA 3 GAA Het None 032-072 Val77Glu GTG 3 CAG Het IVS13 af9; 2T 3 C 034-013 Gln190His CAG 3 CAC Het Gly1961Glu 032-076 Leu244Pro CTG 3 CCG Hom None 032-012 Pro309Arg CCA 3 CGA Het Arg1300Gln 032-054 Phe525Cys TTT 3 TGT Het Ile1846Thr 032-046 Arg537Cys CGT 3 TGT Het Val989Ala 034-038 Arg537Cys CGT 3 TGT Het Gly863Ala 032-095 Leu541Pro18 CTA 3 CCA Het None 034-022 Leu541Pro18 CTA 3 CCA Het Leu2027Phe 035-001 Leu541Pro18 CTA 3 CCA Het None 032-009 Leu541Pro18 CTA 3 CCA Het None 032-023 [Leu541Pro18 ; Ala1038Val27 ] [CTA 3 CCA; GCC 3 GTC] Het Gly863Ala 034-035 [Leu541Pro18 ; Ala1038Val27 ] [CTA 3 CCA; GCC 3 GTC] Het Gly863Ala 032-011 Ala549Pro GCC 3 CCC Het Gly1961Glu 032-044 Gly550Arg GGA 3 AGA Het None 032-085 Arg602Gln CGG 3 CAG Het Val643Met 032-090 Gly607Arg GGG 3 AGG Het Leu2027Phe 032-085 Val643Met GTG 3 ATG Het Arg602Gln 032-042 Val767Asp30 GTC 3 GAG Het Pro1486Leu 071-006 Val767Asp30 GTC 3 GAG Het Ile1562Thr 032-014 Leu797Pro CTG 3 CCG Het Pro1486Leu 032-038 Trp821Arg18 TGG 3 AGG Het None 034-045 Ile824Thr ATC 3 ACC Het Gly1961Glu 032-056 Gly863Ala5 GGA 3 GCA Het None 032-091 Gly863Ala5 GGA 3 GCA Het None 032-020 Gly863Ala5 GGA 3 GCA Het Cys54Tyr 032-023 Gly863Ala5 GGA 3 GCA Het [Leu541Pro; Ala1038Val] 034-011 Gly863Ala5 GGA 3 GCA Het Cys1488Arg 034-015 Gly863Ala5 GGA 3 GCA Het Thr1525Met 034-035 Gly863Ala5 GGA 3 GCA Het [Leu541Pro; Ala1038Val] 034-036 Gly863Ala5 GGA 3 GCA Het Cys2150Arg 034-038 Gly863Ala5 GGA 3 GCA Het Arg537Cys 071-007 Val935Ala GTA 3 GCA Het Cys54Tyr 032-043 Arg943Trp CGG 3 TGG Het Arg1108Leu 032-046 Val989Ala GTT 3 GCT Het Arg537Cys 071-005 Arg1108Cys18 CGC 3 TGC Het None IOVS, September 2001, Vol. 42, No. 10 ABCR in Stargardt Macular Degeneration Patient ID Mutations (Amino Acid Based) Sequence Change (Nucleotide Based) Het/Hom Other Sequence Changes 035-012 Arg1108Cys18 CGC 3 TGC Het Cys54Tyr 032-043 Arg1108Leu5 CGC 3 CTC Het Arg943Trp 032-097 Glu1122Lys18 GAG 3 AAG Het None 035-019 Glu1122Lys18 GAG 3 AAG Het None 071-003 Leu1201Arg15 CTG 3 CGG Het Asn58Lys 032-012 Arg1300Gln CGA 3 CAA Het Pro309Arg 032-068 Arg1300Gln CGA 3 CAA Het None 032-013 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 032-015 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 032-027 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 071-001 Pro1380Leu15 CCG 3 CTG Hom None 034-020 Pro1380Leu15 CCG 3 CTG Het Leu2027Phe 034-028 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 034-044 Pro1380Leu15 CCG 3 CTG Het Leu2027Phe 034-048 Pro1380Leu15 CCG 3 CTG Het Gly1961Glu 035-003 Pro1380Leu15 CCG 3 CTG Het Ile1114(delC) 032-073 Leu1388Pro CTG 3 CCG Het Arg681Ter 034-040 Trp1408Arg15 TGG 3 CGG Het Arg1640Trp 035-013 Trp1408Arg15 TGG 3 CGG Het Arg1640Trp 032-060 Pro1486Leu20 CCA 3 CTA Het [Ser278(delT); Arg1300Gln] 032-014 Pro1486Leu20 CCA 3 CTA Het Leu797Pro 032-025 Pro1486Leu20 CCA 3 CTA Het Asp1531Asn 032-042 Pro1486Leu20 CCA 3 CTA Het Val767Asp 034-011 Cys1488Arg15 TGC 3 CGC Het Gly863Ala 032-034 Cys1490Tyr15 TGC 3 TAC Het Ile1846Thr 032-084 Thr1525Met15 ACG 3 ATG Het Arg2139Trp 032-016 Thr1525Met15 ACG 3 ATG Het Thr1721(delAC) 032-021 Thr1525Met15 ACG 3 ATG Het None 032-041 Thr1525Met15 ACG 3 ATG Het None 034-015 Thr1525Met15 ACG 3 ATG Het Gly863Ala 032-049 Asp1531Asn15 GAC 3 AAC Het Gly1961Glu 034-019 Asp1531Asn15 GAC 3 AAC Het None 032-025 Asp1531Asn15 GAC 3 AAC Het Pro1846Leu 071-006 Ile1562Thr27 ATT 3 ACT Het Val767Asp 034-040 Arg1640Trp18 CGG 3 TGG Het Trp1408Arg 035-013 Arg1640Trp18 CGG 3 TGG Het Trp1408Arg 032-030* Arg1640Gln CGG 3 CAG Hom None 032-019 Pro1776Leu CCC 3 CTC Het Gly1961Glu 032-034 Ile1846Thr21 ATT 3 ACT Het Cys1490Tyr 032-054 Ile1846Thr21 ATT 3 ACT Het Phe525Cys 032-011 Gly1961Glu27 GGA 3 GAA Het Ala549Pro 032-013 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-015 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-019 Gly1961Glu27 GGA 3 GAA Het Pro1776Leu 032-022 Gly1961Glu27 GGA 3 GAA Het IVS41-2delA 032-024 Gly1961Glu27 GGA 3 GAA Het Pro1570(delC) 032-027 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-040 Gly1961Glu27 GGA 3 GAA Het None 032-049 Gly1961Glu27 GGA 3 GAA Het Asp1531Asn 034-013 Gly1961Glu27 GGA 3 GAA Het Gln190His 034-017 Gly1961Glu27 GGA 3 GAA Het Gly2100(delG) 034-021 Gly1961Glu27 GGA 3 GAA Het None 034-025 Gly1961Glu27 GGA 3 GAA Het None 034-028 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 034-031 Gly1961Glu27 GGA 3 GAA Het Leu1741(del11) 034-033 Gly1961Glu27 GGA 3 GAA Het None 034-039 Gly1961Glu27 GGA 3 GAA Het Ser84(insCAAA) 032-050 Gly1961Glu27 GGA 3 GAA Het None 034-045 Gly1961Glu27 GGA 3 GAA Het Ile824Thr 034-048 Gly1961Glu27 GGA 3 GAA Het Pro1380Leu 032-003 Gly1977Ser15 GGC 3 AGC Het Leu2027Phe 032-003 Leu2027Phe5 CTC 3 TTC Het Gly1977Ser 032-090 Leu2027Phe5 CTC 3 TTC Het Gly607Arg 034-006 Leu2027Phe5 CTC 3 TTC Het None 034-020 Leu2027Phe5 CTC 3 TTC Het Pro1380Leu 034-022 Leu2027Phe5 CTC 3 TTC Het Leu541Pro 034-044 Leu2027Phe5 CTC 3 TTC Het Pro1380Leu 035-011 Leu2027Phe5 CTC 3 TTC Het None 032-063 Arg2030Gln15 CGA 3 CAA Het None 032-093 Arg2030Gln15 CGA 3 CAA Het None 2232 Briggs et al. IOVS, September 2001, Vol. 42, No. 10 TABLE 1 (continued). Login to comment

[hide] L- and M-cone-driven electroretinograms in Stargar... Invest Ophthalmol Vis Sci. 2001 May;42(6):1380-9. Scholl HP, Kremers J, Vonthein R, White K, Weber BH
L- and M-cone-driven electroretinograms in Stargardt's macular dystrophy-fundus flavimaculatus.
Invest Ophthalmol Vis Sci. 2001 May;42(6):1380-9., [PMID:11328755]

Abstract [show]
PURPOSE: To study the dynamics of the long (L)- and middle (M)-wavelength-sensitive cone-driven pathways and their interactions in patients with Stargardt's macular dystrophy-fundus flavimaculatus (SMD-FF) and to correlate them with other clinical parameters and individual genotypes. METHODS: Forty-seven patients with SMD-FF participated in the study. In addition to standard 30-Hz flicker electroretinograms (30-Hz fERG), ERG responses were measured to stimuli that modulated exclusively the L or the M cones (L/M cones) or the two simultaneously. Blood samples were screened for mutations in the 50 exons of the ABCA4 gene. RESULTS: Patients with SMD-FF did not show a decrease in the mean L/M-cone-driven ERG sensitivity, but there was a significant increase in the interindividual variability. The mean L-/M-cone weighting ratio was normal. However, the L-cone-driven ERG was significantly phase delayed, whereas the M-cone-driven ERG was significantly phase advanced. These phase changes were significantly correlated with disease duration. The amplitude and implicit time of the standard 30-Hz fERG both correlated significantly with the L/M-cone-driven ERG sensitivity and with the phase difference between the L/M-cone-driven ERGs, indicating the complex origin of the standard 30-Hz fERG. Probable disease-associated mutations in the ABCA4 gene were found in 40 of 45 patients, suggesting that they form a genetically fairly uniform SMD-FF study group. There was no correlation between the genotype and the L/M-cone-driven ERGS: CONCLUSIONS: The changes in L/M-cone-driven ERG sensitivity and phase possibly represent two independent disease processes. The phase changes are similar to those found in patients with retinitis pigmentosa and possibly are a general feature of retinal dystrophies.

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43 Characteristics of the Patients with SMD-FF Patient Sex Age (y) Age at Onset (y) VA CFC DF CV Exon (1) Mut (1) Exon (2) Mut (2) 1 M 32 29 0.6 Moderate ϩ Normal 48 L2241V NF 2 F 39 23 0.4 Moderate - Chaotic 14 W663X 42 G1961E 3 M 34 16 0.1 Moderate ϩ - 42 G1961E NF 4 M 49 17 0.1 Severe ϩ NP 6 G768T/splice 42 G1961E 5 F 36 35 0.6 Moderate ϩ VS (T) 6 C230S 42 G1961E 6 M 28 17 0.1 Mild ϩϩ INS 40 R1898H 43 G1975R 7 M 20 9 0.05 Moderate ϩϩ VS (P/D) 12 ϩ 21 L541P ϩ A1038V 40 IVS40 ϩ 5G 3 A 8 M 33 6 0.1 Mild - Chaotic NF NF 9 M 39 29 0.2 Moderate ϩ VS (P/D) 13 G607R 42 G1961E 10 M 38 22 0.1 Severe ϩ Chaotic NF NF 11 F 28 20 0.7 Mild ϩϩ INS 3 A60T 40 R1898H 12 M 46 30 0.5 Mild ϩ Chaotic 11 E471K 42 G1961E 13 F 25 11 0.1 Moderate ϩϩ S 17 G863A NF 14 F 51 41 0.8 Moderate ϩϩ NP 40 R1898H NF 15 F 23 17 0.1 Mild - Chaotic 3 P68L 36 S1689P 16 F 33 30 0.4 Mild - Chaotic 28 E1399K 42 G1961E 17 F 41 36 0.1 Severe ϩ VS (T) 29 F1440V 37 G1748R 18 M 59 54 0.1 Severe ϩ VS (P/D) 42 G1961E NF 19* M 35 15 0.05 Moderate ϩ Chaotic 17 G863A 37 Q1750X 20* M 43 14 HM Severe ϩϩ NP 17 G863A 37 Q1750X 21 F 46 16 0.1 Moderate ϩ NP NF NF 22 F 32 22 0.05 Moderate ϩ INS 21 A1038V NF 23 M 50 42 0.3 Severe ϩϩ VS (P/D) 12 ϩ 21 L541P ϩ A1038V 17 G863A 24 F 30 14 0.1 Moderate ϩϩ INS 17 G863A 40 IVS40 ϩ 5G 3 A 25 M 36 25 0.5 Moderate ϩϩ - 3 296INSA 21 A1038V 26 M 40 23 0.2 Moderate ϩ S 3 296INSA 42 G1961E 27 F 35 9 0.1 Severe ϩϩ VS (P/D) 22 R1108C NF 28 F 23 18 0.05 Mild ϩϩ S 28 E1399K 43 G1977S 29 F 25 18 0.2 Mild ϩ Chaotic 37 L1763P NF 30 F 16 11 0.1 Moderate ϩ Chaotic 22 R1108C NF 31 M 40 35 0.1 Moderate ϩϩ VS (P/D) 14 R681X NF 32 F 28 27 0.1 Moderate ϩ S 12 ϩ 21 L541P ϩ A1038V 21 A1038V 33 M 32 9 0.05 Severe ϩϩ Chaotic 28 Q1412X 45 R2077W 34 F 23 21 0.2 Moderate ϩ INS 6 G768T/splice NF 35 F 38 33 FC Moderate - Chaotic 17 G863A NF 36 F 39 10 HM Severe ϩϩ NP NF NF 37 F 13 8 0.1 Moderate ϩϩ S - - 38 F 27 25 0.2 Moderate ϩ Chaotic 17 G863A 28 Q1412X 39 M 16 15 0.1 Moderate ϩ VS (P/D) 12 ϩ 17 R572Q ϩ G863A 35 IVS35 ϩ 2T 3 A 40 M 27 26 0.6 Moderate - S 17 G863A NF 41 M 18 16 0.2 Moderate ϩ - - - 42 M 25 24 0.1 Mild - - NF NF 43 F 29 9 0.1 Moderate ϩ Chaotic 12 ϩ 21 L541P ϩ A1038V 42 G1961E 44 M 39 28 0.1 Mild - NP 6 N247S NF 45 F 23 12 0.05 Mild - NP 6 R212C 19 T959I 46 M 43 36 0.2 Moderate ϩ VS (P/D) 21 A1038V NF 47 M 21 18 0.4 Mild ϩϩ INS 28 Q1412X NF Shown are age at examination, age of onset, visual acuity, central fundus changes, and existence and distribution of the typical white-yellow flecks. Login to comment
77 Patient 25 exhibited mild clinical changes, and the genetic analysis revealed a 296insA mutation in exon 3 and an A1038V mutation in exon 21 (Table 1). Login to comment
118 Patient 25, who had a mild phenotype carrying a 296insA mutation in exon 3 and an A1038V mutation in exon 21, exhibited reduced standard 30-Hz-fERG signals that were somewhat advanced compared with the normal subject (A). Login to comment
204 Correlation with Genotype It has been proposed that residual ABCA4 protein activity determines the clinical phenotype of SMD-FF and other related retinal diseases, whereas the pairing of two null or severe mutations is thought to lead to a more severe phenotype resembling a cone-rod dystrophy or inverse RP.33-35 The mutation profile in our group of patients with SMD-FF (with two identified mutations) is in concordance with this model, because only a combination of a mild and severe mutation (e.g., G1961E and 296insA) or of two moderate mutations (e.g., IVS40ϩ5G3A and A1038V) were encountered, whereas the pairing of two null or severe mutations was not observed in our patient sample. Login to comment
44 Characteristics of the Patients with SMD-FF Patient Sex Age (y) Age at Onset (y) VA CFC DF CV Exon (1) Mut (1) Exon (2) Mut (2) 1 M 32 29 0.6 Moderate af9; Normal 48 L2241V NF 2 F 39 23 0.4 Moderate afa; Chaotic 14 W663X 42 G1961E 3 M 34 16 0.1 Moderate af9; - 42 G1961E NF 4 M 49 17 0.1 Severe af9; NP 6 G768T/splice 42 G1961E 5 F 36 35 0.6 Moderate af9; VS (T) 6 C230S 42 G1961E 6 M 28 17 0.1 Mild af9;af9; INS 40 R1898H 43 G1975R 7 M 20 9 0.05 Moderate af9;af9; VS (P/D) 12 af9; 21 L541P af9; A1038V 40 IVS40 af9; 5G 3 A 8 M 33 6 0.1 Mild afa; Chaotic NF NF 9 M 39 29 0.2 Moderate af9; VS (P/D) 13 G607R 42 G1961E 10 M 38 22 0.1 Severe af9; Chaotic NF NF 11 F 28 20 0.7 Mild af9;af9; INS 3 A60T 40 R1898H 12 M 46 30 0.5 Mild af9; Chaotic 11 E471K 42 G1961E 13 F 25 11 0.1 Moderate af9;af9; S 17 G863A NF 14 F 51 41 0.8 Moderate af9;af9; NP 40 R1898H NF 15 F 23 17 0.1 Mild afa; Chaotic 3 P68L 36 S1689P 16 F 33 30 0.4 Mild afa; Chaotic 28 E1399K 42 G1961E 17 F 41 36 0.1 Severe af9; VS (T) 29 F1440V 37 G1748R 18 M 59 54 0.1 Severe af9; VS (P/D) 42 G1961E NF 19* M 35 15 0.05 Moderate af9; Chaotic 17 G863A 37 Q1750X 20* M 43 14 HM Severe af9;af9; NP 17 G863A 37 Q1750X 21 F 46 16 0.1 Moderate af9; NP NF NF 22 F 32 22 0.05 Moderate af9; INS 21 A1038V NF 23 M 50 42 0.3 Severe af9;af9; VS (P/D) 12 af9; 21 L541P af9; A1038V 17 G863A 24 F 30 14 0.1 Moderate af9;af9; INS 17 G863A 40 IVS40 af9; 5G 3 A 25 M 36 25 0.5 Moderate af9;af9; - 3 296INSA 21 A1038V 26 M 40 23 0.2 Moderate af9; S 3 296INSA 42 G1961E 27 F 35 9 0.1 Severe af9;af9; VS (P/D) 22 R1108C NF 28 F 23 18 0.05 Mild af9;af9; S 28 E1399K 43 G1977S 29 F 25 18 0.2 Mild af9; Chaotic 37 L1763P NF 30 F 16 11 0.1 Moderate af9; Chaotic 22 R1108C NF 31 M 40 35 0.1 Moderate af9;af9; VS (P/D) 14 R681X NF 32 F 28 27 0.1 Moderate af9; S 12 af9; 21 L541P af9; A1038V 21 A1038V 33 M 32 9 0.05 Severe af9;af9; Chaotic 28 Q1412X 45 R2077W 34 F 23 21 0.2 Moderate af9; INS 6 G768T/splice NF 35 F 38 33 FC Moderate afa; Chaotic 17 G863A NF 36 F 39 10 HM Severe af9;af9; NP NF NF 37 F 13 8 0.1 Moderate af9;af9; S - - 38 F 27 25 0.2 Moderate af9; Chaotic 17 G863A 28 Q1412X 39 M 16 15 0.1 Moderate af9; VS (P/D) 12 af9; 17 R572Q af9; G863A 35 IVS35 af9; 2T 3 A 40 M 27 26 0.6 Moderate afa; S 17 G863A NF 41 M 18 16 0.2 Moderate af9; - - - 42 M 25 24 0.1 Mild afa; - NF NF 43 F 29 9 0.1 Moderate af9; Chaotic 12 af9; 21 L541P af9; A1038V 42 G1961E 44 M 39 28 0.1 Mild afa; NP 6 N247S NF 45 F 23 12 0.05 Mild afa; NP 6 R212C 19 T959I 46 M 43 36 0.2 Moderate af9; VS (P/D) 21 A1038V NF 47 M 21 18 0.4 Mild af9;af9; INS 28 Q1412X NF Shown are age at examination, age of onset, visual acuity, central fundus changes, and existence and distribution of the typical white-yellow flecks. Login to comment
78 Patient 25 exhibited mild clinical changes, and the genetic analysis revealed a 296insA mutation in exon 3 and an A1038V mutation in exon 21 (Table 1). Login to comment
119 Patient 25, who had a mild phenotype carrying a 296insA mutation in exon 3 and an A1038V mutation in exon 21, exhibited reduced standard 30-Hz-fERG signals that were somewhat advanced compared with the normal subject (A). Login to comment
205 Correlation with Genotype It has been proposed that residual ABCA4 protein activity determines the clinical phenotype of SMD-FF and other related retinal diseases, whereas the pairing of two null or severe mutations is thought to lead to a more severe phenotype resembling a cone-rod dystrophy or inverse RP.33-35 The mutation profile in our group of patients with SMD-FF (with two identified mutations) is in concordance with this model, because only a combination of a mild and severe mutation (e.g., G1961E and 296insA) or of two moderate mutations (e.g., IVS40af9;5G3A and A1038V) were encountered, whereas the pairing of two null or severe mutations was not observed in our patient sample. Login to comment

[hide] An analysis of allelic variation in the ABCA4 gene... Invest Ophthalmol Vis Sci. 2001 May;42(6):1179-89. Webster AR, Heon E, Lotery AJ, Vandenburgh K, Casavant TL, Oh KT, Beck G, Fishman GA, Lam BL, Levin A, Heckenlively JR, Jacobson SG, Weleber RG, Sheffield VC, Stone EM
An analysis of allelic variation in the ABCA4 gene.
Invest Ophthalmol Vis Sci. 2001 May;42(6):1179-89., [PMID:11328725]

Abstract [show]
PURPOSE: To assess the allelic variation of the ATP-binding transporter protein (ABCA4). METHODS: A combination of single-strand conformation polymorphism (SSCP) and automated DNA sequencing was used to systematically screen this gene for sequence variations in 374 unrelated probands with a clinical diagnosis of Stargardt disease, 182 patients with age-related macular degeneration (AMD), and 96 normal subjects. RESULTS: There was no significant difference in the proportion of any single variant or class of variant between the control and AMD groups. In contrast, truncating variants, amino acid substitutions, synonymous codon changes, and intronic variants were significantly enriched in patients with Stargardt disease when compared with their presence in subjects without Stargardt disease (Kruskal-Wallis P < 0.0001 for each variant group). Overall, there were 2480 instances of 213 different variants in the ABCA4 gene, including 589 instances of 97 amino acid substitutions, and 45 instances of 33 truncating variants. CONCLUSIONS: Of the 97 amino acid substitutions, 11 occurred at a frequency that made them unlikely to be high-penetrance recessive disease-causing variants (HPRDCV). After accounting for variants in cis, one or more changes that were compatible with HPRDCV were found on 35% of all Stargardt-associated alleles overall. The nucleotide diversity of the ABCA4 coding region, a collective measure of the number and prevalence of polymorphic sites in a region of DNA, was found to be 1.28, a value that is 9 to 400 times greater than that of two other macular disease genes that were examined in a similar fashion (VMD2 and EFEMP1).

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102 Thirty-Three Truncated and 98 Amino Acid-Changing Variants in the ABCA4 Gene Exon Nucleotide Change Effect (A) (B) AMD (n ‫؍‬ 182) Control (n ‫؍‬ 96) STGD (n ‫؍‬ 374) Allele Prevalence 2 106delT FS NS 0 0 1 Ͻ0.01 2 160 ϩ 1g 3 a Splice site NS 0 0 1 Ͻ0.01 3 161G 3 A Cys54Tyr NS 0 0 6 Ͻ0.01 3 179C 3 T Ala60Val NS 0 0 2 Ͻ0.01 3 194G 3 A Gly65Glu NS 0 0 2 Ͻ0.01 3 223T 3 G Cys75Gly NS 0 0 2 Ͻ0.01 3 247delCAAA FS NS 0 0 2 Ͻ0.01 3 298C 3 T Ser100Pro NS 0 0 1 Ͻ0.01 5 454C 3 T Arg152Stop NS 0 0 2 Ͻ0.01 6 574G 3 A Ala192Thr NS 0 0 1 Ͻ0.01 6 618C 3 G Ser206Arg NS 0 0 3 Ͻ0.01 6 634C 3 T Arg212Cys 0.02 Yes 0 0 7 0.01 6 635G 3 A Arg212His NS 2 2 6 0.01 6 658C 3 T Arg220Cys NS 0 0 2 Ͻ0.01 6 661delG FS NS 0 0 1 Ͻ0.01 666delAAAGACGGTGC 6 GC FS NS 0 0 1 Ͻ0.01 6 746A 3 C Asp249Gly NS 0 0 1 Ͻ0.01 8 899C 3 A Thr300Asn NS 0 0 1 Ͻ0.01 8 997C 3 T Arg333Trp NS 0 0 1 Ͻ0.01 9 1140T 3 A Asn380Lys NS 0 0 1 Ͻ0.01 9 1222C 3 T Arg408Stop NS 0 0 1 Ͻ0.01 10 1268A 3 G His423Arg NS 1 0 7 0.01 10 1335C 3 G Ser445Arg NS 0 0 1 Ͻ0.01 10 1344delG FS NS 0 0 1 Ͻ0.01 11 1411G 3 A Glu471Lys NS 0 0 3 Ͻ0.01 11 1513delATCAC FS NS 0 0 1 Ͻ0.01 12 1622T 3 C Leu541Pro 0.001 Yes 0 0 11 0.01 13 1804C 3 T Arg602Trp NS 0 0 3 Ͻ0.01 13 1805G 3 A Arg602Gln NS 0 0 1 Ͻ0.01 13 1819G 3 T Gly607Trp NS 0 0 1 Ͻ0.01 13 1823T 3 A Phe608Ile NS 0 0 1 Ͻ0.01 13 1927G 3 A Val643Met NS 0 0 1 Ͻ0.01 14 1989G 3 T Trp663Stop NS 0 0 1 Ͻ0.01 14 2005delAT FS NS 0 0 3 Ͻ0.01 14 2041C 3 T Arg681Stop NS 0 0 2 Ͻ0.01 14 2147C 3 T Thr716Met NS 0 0 1 Ͻ0.01 15 2291G 3 A Cys764Tyr NS 0 0 1 Ͻ0.01 15 2294G 3 A Ser765Asn NS 0 0 1 Ͻ0.01 15 2300T 3 A Val767Asp NS 0 0 2 Ͻ0.01 16 2385del16bp FS NS 0 0 1 Ͻ0.01 16 2453G 3 A Gly818Glu NS 0 0 1 Ͻ0.01 16 2461T 3 A Trp821Arg NS 0 0 1 Ͻ0.01 16 2546T 3 C Val849Ala NS 0 0 4 Ͻ0.01 16 2552G 3 A Gly851Asp NS 0 0 1 Ͻ0.01 16 2560G 3 A Ala854Thr NS 0 0 1 Ͻ0.01 17 2588G 3 C Gly863Ala 0.0006 No 2 2 28 0.02 17 2617T 3 C Phe873Leu NS 0 0 1 Ͻ0.01 18 2690C 3 T Thr897Ile NS 0 0 1 Ͻ0.01 18 2701A 3 G Thr901Ala NS 0 1 0 Ͻ0.01 18 2703A 3 G Thr901Arg NS 0 0 2 Ͻ0.01 19 2828G 3 A Arg943Gln NS 20 13 37 0.05 19 2883delC FS NS 0 0 1 Ͻ0.01 20 2894A 3 G Asn965Ser NS 0 0 3 Ͻ0.01 19 2912C 3 A Thr971Asn NS 0 0 1 Ͻ0.01 19 2915C 3 A Thr972Asn NS 0 0 1 Ͻ0.01 20 2920T 3 C Ser974Pro NS 0 0 1 Ͻ0.01 20 2966T 3 C Val989Ala NS 0 0 2 Ͻ0.01 20 2977del8bp FS NS 0 0 1 Ͻ0.01 20 3041T 3 G Leu1014Arg NS 0 0 1 Ͻ0.01 21 3055A 3 G Thr1019Ala NS 0 0 1 Ͻ0.01 21 3064G 3 A Glu1022Lys NS 0 0 1 Ͻ0.01 21 3091A 3 G Lys1031Glu NS 0 0 1 Ͻ0.01 21 3113G 3 T Ala1038Val 0.001 Yes 1 0 17 0.01 22 3205insAA FS NS 0 0 1 Ͻ0.01 22 3261G 3 A Glu1087Lys NS 0 0 2 Ͻ0.01 22 3322C 3 T Arg1108Cys 0.04 Yes 0 0 6 Ͻ0.01 22 3323G 3 A Arg1108His NS 0 0 1 Ͻ0.01 23 3364G 3 A Glu1122Lys NS 0 0 1 Ͻ0.01 (continues) Exon Nucleotide Change Effect (A) (B) AMD (n ‫؍‬ 182) Control (n ‫؍‬ 96) STGD (n ‫؍‬ 374) Allele Prevalence 23 3386G 3 T Arg1129Leu NS 0 0 3 Ͻ0.01 24 3531C 3 A Cys1158Stop NS 0 0 1 Ͻ0.01 25 3749T 3 C Leu1250Pro NS 0 0 1 Ͻ0.01 26 3835delGATTCT FS NS 0 0 1 Ͻ0.01 27 3940C 3 A Pro1314Thr NS 0 1 0 Ͻ0.01 28 4139C 3 T Pro1380Leu 0.001 Yes 0 0 10 0.01 28 4222T 3 C Trp1408Arg NS 0 0 2 Ͻ0.01 28 4223G 3 T Trp1408Leu NS 0 0 2 Ͻ0.01 28 4234C 3 T Gln1412stop NS 0 0 1 Ͻ0.01 29 4297G 3 A Val1433Ile NS 1 0 0 Ͻ0.01 29 4319T 3 C Phe1440Ser NS 0 0 1 Ͻ0.01 30 4353 - 1g 3 t Splice site NS 0 0 1 Ͻ0.01 30 4457C 3 T Pro1486Leu NS 0 0 1 Ͻ0.01 30 4462T 3 C Cys1488Arg NS 0 0 3 Ͻ0.01 30 4463G 3 T Cys1488Phe NS 0 0 2 Ͻ0.01 30 4469G 3 A Cys1490Tyr NS 0 0 3 Ͻ0.01 30 4531insC FS NS 0 0 2 Ͻ0.01 32 4538A 3 G Gln1513Arg NS 0 0 1 Ͻ0.01 30 4539 ϩ 1g 3 t Splice site NS 0 0 1 Ͻ0.01 31 4574T 3 C Leu1525Pro NS 0 0 1 Ͻ0.01 33 4733delGTTT FS NS 0 0 1 Ͻ0.01 4859delATAACAinsTCC 35 T FS NS 0 0 1 Ͻ0.01 36 4909G 3 A Ala1637Thr NS 0 0 1 Ͻ0.01 35 4918C 3 T Arg1640Trp NS 0 0 1 Ͻ0.01 35 4919G 3 A Arg1640Gln NS 0 0 1 Ͻ0.01 35 4954T 3 G Tyr1652Asp NS 0 0 1 Ͻ0.01 36 5077G 3 A Val1693Ile NS 0 0 1 Ͻ0.01 36 5186T 3 C Leu1729Pro NS 0 0 2 Ͻ0.01 36 5206T 3 C Ser1736Pro NS 0 0 1 Ͻ0.01 36 5212del11bp FS NS 0 0 1 Ͻ0.01 37 5225delTGGTGGTGGGC FS NS 0 0 1 Ͻ0.01 del LPA 37 5278del9bp 1760 NS 0 0 1 Ͻ0.01 37 5288delG FS NS 0 0 1 Ͻ0.01 38 5395A 3 G Asn1799Asp NS 0 0 1 Ͻ0.01 38 5451T 3 G Asp1817Glu NS 1 0 4 Ͻ0.01 39 5584 ϩ 5g 3 a Splice site 0.02 Yes 0 0 6 Ͻ0.01 40 5603A 3 T Asn1868Ile 0.0006 No 20 7 79 0.08 40 5651T 3 A Val1884GLu NS 0 0 1 Ͻ0.01 40 5657G 3 A Gly1886Glu NS 0 0 1 Ͻ0.01 40 5687T 3 A Val1896Asp NS 0 0 1 Ͻ0.01 40 5693G 3 A Arg1898His NS 0 0 1 Ͻ0.01 40 5714 ϩ 5g 3 a Splice site NS 0 0 1 Ͻ0.01 42 5843CA 3 TG Pro1948Leu NS 11 7 28 0.04 42 5882G 3 A Gly1961Glu Ͻ0.0001 Yes 1 0 43 0.03 43 5908C 3 T Leu1970Phe NS 1 0 1 Ͻ0.01 43 5917delG FS NS 0 0 1 Ͻ0.01 44 6079C 3 T Leu2027Phe 0.01 Yes 0 0 9 0.01 44 6088C 3 T Arg2030Stop NS 0 0 2 Ͻ0.01 44 6089G 3 A Arg2030Gln NS 0 0 1 Ͻ0.01 44 6112A 3 T Arg2038Trp NS 0 0 1 Ͻ0.01 45 6148A 3 C Val2050Leu NS 1 0 0 Ͻ0.01 46 6212A 3 T Tyr2071Phe NS 0 0 1 Ͻ0.01 45 6229C 3 T Arg2077Trp NS 0 0 2 Ͻ0.01 46 6320G 3 A Arg2107His 0.01 Yes 0 0 10 0.01 46 6383A 3 G His2128Arg NS 0 0 1 Ͻ0.01 47 6446G 3 T Arg2149Leu NS 0 0 1 Ͻ0.01 47 6449G 3 A Cys2150Tyr NS 0 0 5 Ͻ0.01 48 6529G 3 A Asp2177Asn NS 2 0 0 Ͻ0.01 48 6686T 3 C Leu2229Pro NS 0 0 1 Ͻ0.01 48 6707delTCACACAG FS NS 0 0 1 Ͻ0.01 48 6729 ϩ 1g 3 a Splice site NS 0 0 1 Ͻ0.01 49 6764G 3 T Ser2255Ile 0.009 No 16 4 54 0.06 49 6788G 3 T Arg2263Leu NS 0 0 1 Ͻ0.01 (A) The probability under the null hypothesis of similar prevalence of each variant in Stargardt (STGD) compared with non-STGD alleles (two-tailed Fisher`s exact test); (B) compatability of the variant existing in a ratio of 100:1 in STGD to control alleles, calculated using the binomial distribution. 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148 These included three nonconservative changes, Gly1961Glu, Arg1108Cys, and Arg212Cys, and five other changes that were conservative by our criteria, Leu541Pro, Ala1038Val, Pro1380Leu, Leu2027Phe, and Arg2107His. Login to comment
177 Similarly, Leu541Pro occurred in 10 patients with Stargardt disease who harbored the variant Ala1038Val, and, when phase could be determined, these variations were found in cis. Login to comment
178 One patient with Stargardt disease bore Leu541Pro without the Ala1038Val variant, and seven harbored the Ala1038Val change without Leu541Pro. Login to comment
179 Ala1038Val without Leu541Pro was also found in one patient with AMD. Login to comment
182 Considering only those variants predicted to cause protein truncation and missense changes compatible with disease association, we found 1 patient with five such variants, 11 with three, and a further 6 with two (Leu541Pro and Ala1038Val) that were on the same chromosome. Login to comment
103 Thirty-Three Truncated and 98 Amino Acid-Changing Variants in the ABCA4 Gene Exon Nucleotide Change Effect (A) (B) AMD (n d1d; 182) Control (n d1d; 96) STGD (n d1d; 374) Allele Prevalence 2 106delT FS NS 0 0 1 b0d;0.01 2 160 af9; 1g 3 a Splice site NS 0 0 1 b0d;0.01 3 161G 3 A Cys54Tyr NS 0 0 6 b0d;0.01 3 179C 3 T Ala60Val NS 0 0 2 b0d;0.01 3 194G 3 A Gly65Glu NS 0 0 2 b0d;0.01 3 223T 3 G Cys75Gly NS 0 0 2 b0d;0.01 3 247delCAAA FS NS 0 0 2 b0d;0.01 3 298C 3 T Ser100Pro NS 0 0 1 b0d;0.01 5 454C 3 T Arg152Stop NS 0 0 2 b0d;0.01 6 574G 3 A Ala192Thr NS 0 0 1 b0d;0.01 6 618C 3 G Ser206Arg NS 0 0 3 b0d;0.01 6 634C 3 T Arg212Cys 0.02 Yes 0 0 7 0.01 6 635G 3 A Arg212His NS 2 2 6 0.01 6 658C 3 T Arg220Cys NS 0 0 2 b0d;0.01 6 661delG FS NS 0 0 1 b0d;0.01 666delAAAGACGGTGC 6 GC FS NS 0 0 1 b0d;0.01 6 746A 3 C Asp249Gly NS 0 0 1 b0d;0.01 8 899C 3 A Thr300Asn NS 0 0 1 b0d;0.01 8 997C 3 T Arg333Trp NS 0 0 1 b0d;0.01 9 1140T 3 A Asn380Lys NS 0 0 1 b0d;0.01 9 1222C 3 T Arg408Stop NS 0 0 1 b0d;0.01 10 1268A 3 G His423Arg NS 1 0 7 0.01 10 1335C 3 G Ser445Arg NS 0 0 1 b0d;0.01 10 1344delG FS NS 0 0 1 b0d;0.01 11 1411G 3 A Glu471Lys NS 0 0 3 b0d;0.01 11 1513delATCAC FS NS 0 0 1 b0d;0.01 12 1622T 3 C Leu541Pro 0.001 Yes 0 0 11 0.01 13 1804C 3 T Arg602Trp NS 0 0 3 b0d;0.01 13 1805G 3 A Arg602Gln NS 0 0 1 b0d;0.01 13 1819G 3 T Gly607Trp NS 0 0 1 b0d;0.01 13 1823T 3 A Phe608Ile NS 0 0 1 b0d;0.01 13 1927G 3 A Val643Met NS 0 0 1 b0d;0.01 14 1989G 3 T Trp663Stop NS 0 0 1 b0d;0.01 14 2005delAT FS NS 0 0 3 b0d;0.01 14 2041C 3 T Arg681Stop NS 0 0 2 b0d;0.01 14 2147C 3 T Thr716Met NS 0 0 1 b0d;0.01 15 2291G 3 A Cys764Tyr NS 0 0 1 b0d;0.01 15 2294G 3 A Ser765Asn NS 0 0 1 b0d;0.01 15 2300T 3 A Val767Asp NS 0 0 2 b0d;0.01 16 2385del16bp FS NS 0 0 1 b0d;0.01 16 2453G 3 A Gly818Glu NS 0 0 1 b0d;0.01 16 2461T 3 A Trp821Arg NS 0 0 1 b0d;0.01 16 2546T 3 C Val849Ala NS 0 0 4 b0d;0.01 16 2552G 3 A Gly851Asp NS 0 0 1 b0d;0.01 16 2560G 3 A Ala854Thr NS 0 0 1 b0d;0.01 17 2588G 3 C Gly863Ala 0.0006 No 2 2 28 0.02 17 2617T 3 C Phe873Leu NS 0 0 1 b0d;0.01 18 2690C 3 T Thr897Ile NS 0 0 1 b0d;0.01 18 2701A 3 G Thr901Ala NS 0 1 0 b0d;0.01 18 2703A 3 G Thr901Arg NS 0 0 2 b0d;0.01 19 2828G 3 A Arg943Gln NS 20 13 37 0.05 19 2883delC FS NS 0 0 1 b0d;0.01 20 2894A 3 G Asn965Ser NS 0 0 3 b0d;0.01 19 2912C 3 A Thr971Asn NS 0 0 1 b0d;0.01 19 2915C 3 A Thr972Asn NS 0 0 1 b0d;0.01 20 2920T 3 C Ser974Pro NS 0 0 1 b0d;0.01 20 2966T 3 C Val989Ala NS 0 0 2 b0d;0.01 20 2977del8bp FS NS 0 0 1 b0d;0.01 20 3041T 3 G Leu1014Arg NS 0 0 1 b0d;0.01 21 3055A 3 G Thr1019Ala NS 0 0 1 b0d;0.01 21 3064G 3 A Glu1022Lys NS 0 0 1 b0d;0.01 21 3091A 3 G Lys1031Glu NS 0 0 1 b0d;0.01 21 3113G 3 T Ala1038Val 0.001 Yes 1 0 17 0.01 22 3205insAA FS NS 0 0 1 b0d;0.01 22 3261G 3 A Glu1087Lys NS 0 0 2 b0d;0.01 22 3322C 3 T Arg1108Cys 0.04 Yes 0 0 6 b0d;0.01 22 3323G 3 A Arg1108His NS 0 0 1 b0d;0.01 23 3364G 3 A Glu1122Lys NS 0 0 1 b0d;0.01 (continues) Exon Nucleotide Change Effect (A) (B) AMD (n d1d; 182) Control (n d1d; 96) STGD (n d1d; 374) Allele Prevalence 23 3386G 3 T Arg1129Leu NS 0 0 3 b0d;0.01 24 3531C 3 A Cys1158Stop NS 0 0 1 b0d;0.01 25 3749T 3 C Leu1250Pro NS 0 0 1 b0d;0.01 26 3835delGATTCT FS NS 0 0 1 b0d;0.01 27 3940C 3 A Pro1314Thr NS 0 1 0 b0d;0.01 28 4139C 3 T Pro1380Leu 0.001 Yes 0 0 10 0.01 28 4222T 3 C Trp1408Arg NS 0 0 2 b0d;0.01 28 4223G 3 T Trp1408Leu NS 0 0 2 b0d;0.01 28 4234C 3 T Gln1412stop NS 0 0 1 b0d;0.01 29 4297G 3 A Val1433Ile NS 1 0 0 b0d;0.01 29 4319T 3 C Phe1440Ser NS 0 0 1 b0d;0.01 30 4353 afa; 1g 3 t Splice site NS 0 0 1 b0d;0.01 30 4457C 3 T Pro1486Leu NS 0 0 1 b0d;0.01 30 4462T 3 C Cys1488Arg NS 0 0 3 b0d;0.01 30 4463G 3 T Cys1488Phe NS 0 0 2 b0d;0.01 30 4469G 3 A Cys1490Tyr NS 0 0 3 b0d;0.01 30 4531insC FS NS 0 0 2 b0d;0.01 32 4538A 3 G Gln1513Arg NS 0 0 1 b0d;0.01 30 4539 af9; 1g 3 t Splice site NS 0 0 1 b0d;0.01 31 4574T 3 C Leu1525Pro NS 0 0 1 b0d;0.01 33 4733delGTTT FS NS 0 0 1 b0d;0.01 4859delATAACAinsTCC 35 T FS NS 0 0 1 b0d;0.01 36 4909G 3 A Ala1637Thr NS 0 0 1 b0d;0.01 35 4918C 3 T Arg1640Trp NS 0 0 1 b0d;0.01 35 4919G 3 A Arg1640Gln NS 0 0 1 b0d;0.01 35 4954T 3 G Tyr1652Asp NS 0 0 1 b0d;0.01 36 5077G 3 A Val1693Ile NS 0 0 1 b0d;0.01 36 5186T 3 C Leu1729Pro NS 0 0 2 b0d;0.01 36 5206T 3 C Ser1736Pro NS 0 0 1 b0d;0.01 36 5212del11bp FS NS 0 0 1 b0d;0.01 37 5225delTGGTGGTGGGC FS NS 0 0 1 b0d;0.01 del LPA 37 5278del9bp 1760 NS 0 0 1 b0d;0.01 37 5288delG FS NS 0 0 1 b0d;0.01 38 5395A 3 G Asn1799Asp NS 0 0 1 b0d;0.01 38 5451T 3 G Asp1817Glu NS 1 0 4 b0d;0.01 39 5584 af9; 5g 3 a Splice site 0.02 Yes 0 0 6 b0d;0.01 40 5603A 3 T Asn1868Ile 0.0006 No 20 7 79 0.08 40 5651T 3 A Val1884GLu NS 0 0 1 b0d;0.01 40 5657G 3 A Gly1886Glu NS 0 0 1 b0d;0.01 40 5687T 3 A Val1896Asp NS 0 0 1 b0d;0.01 40 5693G 3 A Arg1898His NS 0 0 1 b0d;0.01 40 5714 af9; 5g 3 a Splice site NS 0 0 1 b0d;0.01 42 5843CA 3 TG Pro1948Leu NS 11 7 28 0.04 42 5882G 3 A Gly1961Glu b0d;0.0001 Yes 1 0 43 0.03 43 5908C 3 T Leu1970Phe NS 1 0 1 b0d;0.01 43 5917delG FS NS 0 0 1 b0d;0.01 44 6079C 3 T Leu2027Phe 0.01 Yes 0 0 9 0.01 44 6088C 3 T Arg2030Stop NS 0 0 2 b0d;0.01 44 6089G 3 A Arg2030Gln NS 0 0 1 b0d;0.01 44 6112A 3 T Arg2038Trp NS 0 0 1 b0d;0.01 45 6148A 3 C Val2050Leu NS 1 0 0 b0d;0.01 46 6212A 3 T Tyr2071Phe NS 0 0 1 b0d;0.01 45 6229C 3 T Arg2077Trp NS 0 0 2 b0d;0.01 46 6320G 3 A Arg2107His 0.01 Yes 0 0 10 0.01 46 6383A 3 G His2128Arg NS 0 0 1 b0d;0.01 47 6446G 3 T Arg2149Leu NS 0 0 1 b0d;0.01 47 6449G 3 A Cys2150Tyr NS 0 0 5 b0d;0.01 48 6529G 3 A Asp2177Asn NS 2 0 0 b0d;0.01 48 6686T 3 C Leu2229Pro NS 0 0 1 b0d;0.01 48 6707delTCACACAG FS NS 0 0 1 b0d;0.01 48 6729 af9; 1g 3 a Splice site NS 0 0 1 b0d;0.01 49 6764G 3 T Ser2255Ile 0.009 No 16 4 54 0.06 49 6788G 3 T Arg2263Leu NS 0 0 1 b0d;0.01 (A) The probability under the null hypothesis of similar prevalence of each variant in Stargardt (STGD) compared with non-STGD alleles (two-tailed Fisher`s exact test); (B) compatability of the variant existing in a ratio of 100:1 in STGD to control alleles, calculated using the binomial distribution. 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149 These included three nonconservative changes, Gly1961Glu, Arg1108Cys, and Arg212Cys, and five other changes that were conservative by our criteria, Leu541Pro, Ala1038Val, Pro1380Leu, Leu2027Phe, and Arg2107His. Login to comment
180 One patient with Stargardt disease bore Leu541Pro without the Ala1038Val variant, and seven harbored the Ala1038Val change without Leu541Pro. Login to comment
181 Ala1038Val without Leu541Pro was also found in one patient with AMD. Login to comment
184 Considering only those variants predicted to cause protein truncation and missense changes compatible with disease association, we found 1 patient with five such variants, 11 with three, and a further 6 with two (Leu541Pro and Ala1038Val) that were on the same chromosome. Login to comment

[hide] Late-onset Stargardt disease is associated with mi... Hum Genet. 2001 Apr;108(4):346-55. Yatsenko AN, Shroyer NF, Lewis RA, Lupski JR
Late-onset Stargardt disease is associated with missense mutations that map outside known functional regions of ABCR (ABCA4).
Hum Genet. 2001 Apr;108(4):346-55., [PMID:11379881]

Abstract [show]
Based on recent studies of the photoreceptor-specific ABC transporter gene ABCR (ABCA4) in Stargardt disease (STGD1) and other retinal dystrophies, we and others have developed a model in which the severity of retinal disease correlates inversely with residual ABCR activity. This model predicts that patients with late-onset STGDI may retain partial ABCR activity attributable to mild missense alleles. To test this hypothesis, we used late-onset STGDI patients (onset: > or =35 years) to provide an in vivo functional analysis of various combinations of mutant alleles. We sequenced directly the entire coding region of ABCR and detected mutations in 33/50 (66%) disease chromosomes, but surprisingly, 11/33 (33%) were truncating alleles. Importantly, all 22 missense mutations were located outside the known functional domains of ABCR (ATP-binding or transmembrane), whereas in our general cohort of STGDI subjects, alterations occurred with equal frequency across the entire protein. We suggest that these missense mutations in regions of unknown function are milder alleles and more susceptible to modifier effects. Thus, we have corroborated a prediction from the model of ABCR pathogenicity that (1) one mutant ABCR allele is always missense in late-onset STGD1 patients, and (2) the age-of-onset is correlated with the amount of ABCR activity of this allele. In addition, we report three new pseudodominant families that now comprise eight of 178 outbred STGD1 families and suggest a carrier frequency of STGD1-associated ABCR mutations of about 4.5% (approximately 1/22).

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61 Overall, these 33 mutant alleles represent 24 different ABCR alterations; 22 of 33 (66%) mutant alleles represent 15 different missense amino acid changes (one complex allele consisted of two missense mutations [L541P; A1038V]; Table 1, Fig.2). Login to comment
65 Allele 1 nucleotide Amino acid Allele 2 Amino acid Age of change nucleotide change onset (years) AR129-08 37 AR140-01 6079C→T L2027F 3322C→T R1108C 36 AR204-04 35 AR280-03 6316C→T R2106C 6710insA T2237fs 35 AR311-04 4462T→C C1488R 35 AR336-03 2588G→C G863A 5898+1G→A E1966splice 39 AR343-06 2588G→C G863A 3322C→T R1108C 43 AR387-03 4919G→A R1640Q 2971G→C G991R 40 AR410-04 768G→T V256splice 3113C→T A1038V 38 AR440-03 6238-6239del2 bp S2080fs 44 AR448-01a 454C→T R152X 6089G→A R2030Q 52 AR452-04 2005-2006del2 bp M669fs 6089G→A R2030Q 40 AR455-05 [1622T→C;3113C→T] [L541P;A1038V] 43 AR474-02 36 AR516-01a 5196+1G→A I1732splice 3113C→T A1038V 47 AR518-03 3322C→T R1108C 35 AR540-01a 4685T→C I1562T 51 AR594-02a 5196+1G→A I1732splice 36 AR606-04 3322C→T R1108C 2588G→C G863A 39 AR608-02 1025-1038del14 bp D342fs 40 AR617-03 2827C→T R943W 39 AR632-02a 3386G→T R1129L 50 AR649-03 3303G→A W1101X 3113C→T A1038V 36 AR662-02a 1015T→G W339G 50 AR723-01a 3602T→G L1201R 65 Fig.1 Pedigrees of late-onset Stargardt disease families (filled symbols STGD1-affected individuals). Login to comment
71 Each of the two more common mutations, A1038V and R1108C, was identified in four disease chromosomes and together comprised 24% (8/33) of identified mutant alleles. Login to comment
111 To compare this observation directly with our previous report (Lewis et al. 1999), we replaced five mutations (A1038V, L2027F, R2030Q, R2038W, V2050L) to linker regions. Login to comment
134 Conversely, missense mutations located in other regions (e.g., missense mutations in late-onset STGD1) might retain some ABCR activity. This hypothesis is supported by the observations of Sun et al. (2000) that ABCR missense mutations located outside the known functional domains (L541P, G863A, A1038V, R1108C, R1129L, C1488R, R2106C) have a milder functional effect on expression and ATP-binding activity (1/3-2/3 activity of wild-type). Login to comment

[hide] Simple and complex ABCR: genetic predisposition to... Am J Hum Genet. 2000 Oct;67(4):793-9. Epub 2000 Sep 1. Allikmets R
Simple and complex ABCR: genetic predisposition to retinal disease.
Am J Hum Genet. 2000 Oct;67(4):793-9. Epub 2000 Sep 1., [PMID:10970771]

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29 What makes ABCR an even more difficult diagnostic target than CFTR is that, across all populations studied, the most-frequent disease-associated ABCR alleles-for example, G1961E, G863A/ delG863, and A1038V-have been described in ~10% of patients with STGD, whereas the delF508 allele of CFTR accounts for close to 70% of all cystic fibrosis alleles (Zielenski and Tsui 1995). Login to comment
40 Second, both studies have identified a frequent, complex allele, L541P/A1038V, in patients of German origin who have both STGD and CRD (Maugeri et al. 2000 [in this issue]; Rivera et al. 2000 [in this issue]). Login to comment
46 In addition, the complexity of the genotype/phenotype-correlation studies in ABCR-related retinal dystrophies is underlined by the fact that two patients homozygous for the L541P/A1038V allele were diagnosed with CRD and STGD (Maugeri et al. 2000 [in this issue]; Rivera et al. 2000 [in this issue]). Login to comment
124 Last, both mutations found on the "German" complex allele, L541P and A1038V, even if analyzed separately, render the ABCR protein defective (Sun et al. 2000). Login to comment

[hide] A comprehensive survey of sequence variation in th... Am J Hum Genet. 2000 Oct;67(4):800-13. Epub 2000 Aug 24. Rivera A, White K, Stohr H, Steiner K, Hemmrich N, Grimm T, Jurklies B, Lorenz B, Scholl HP, Apfelstedt-Sylla E, Weber BH
A comprehensive survey of sequence variation in the ABCA4 (ABCR) gene in Stargardt disease and age-related macular degeneration.
Am J Hum Genet. 2000 Oct;67(4):800-13. Epub 2000 Aug 24., [PMID:10958763]

Abstract [show]
Stargardt disease (STGD) is a common autosomal recessive maculopathy of early and young-adult onset and is caused by alterations in the gene encoding the photoreceptor-specific ATP-binding cassette (ABC) transporter (ABCA4). We have studied 144 patients with STGD and 220 unaffected individuals ascertained from the German population, to complete a comprehensive, population-specific survey of the sequence variation in the ABCA4 gene. In addition, we have assessed the proposed role for ABCA4 in age-related macular degeneration (AMD), a common cause of late-onset blindness, by studying 200 affected individuals with late-stage disease. Using a screening strategy based primarily on denaturing gradient gel electrophoresis, we have identified in the three study groups a total of 127 unique alterations, of which 90 have not been previously reported, and have classified 72 as probable pathogenic mutations. Of the 288 STGD chromosomes studied, mutations were identified in 166, resulting in a detection rate of approximately 58%. Eight different alleles account for 61% of the identified disease alleles, and at least one of these, the L541P-A1038V complex allele, appears to be a founder mutation in the German population. When the group with AMD and the control group were analyzed with the same methodology, 18 patients with AMD and 12 controls were found to harbor possible disease-associated alterations. This represents no significant difference between the two groups; however, for detection of modest effects of rare alleles in complex diseases, the analysis of larger cohorts of patients may be required.

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7 Eight different alleles account for 61% of the identified disease alleles, and at least one of these, the L541P-A1038V complex allele, appears to be a founder mutation in the German population. Login to comment
22 Certain mutant alleles-for example, G863A, A1038V, and G1961E-appear to be more common and may have altered frequencies in different populations, as a result of founder effect (Maugeri et al. 1999; Simonelli et al. 2000). Login to comment
80 Nucleotide alterations occurring in sim- Table 2 ABCA4 Mutations Found in Patients with STGD and AMD and in Controls EXON AND NUCLEOTIDE CHANGE EFFECT NO. OF ALLELES REFERENCE(S) STGD (288) AMD (400) Control (440) 3: 178GrA A60T 1 0 0 This study 179CrT A60E 1 0 0 This study 194GrA G65E 1 0 0 Fishman et al. (1999) 203CrT P68L 1 0 0 This study 214GrA G72R 1 0 0 This study 296insA Frameshift 2 0 0 This study 5: 454CrT R152X 1 0 0 This study 6: 634CrT R212C 1 0 0 Lewis et al. (1999) 688TrA C230S 1 0 0 This study 730delCT Frameshift 1 0 0 This study 740ArG N247S 1 0 0 This study 768GrT Splice 2 0 0 Maugeri et al. (1999) 8: 983ArT E328V 1a 0 0 This study 1086TrA Y362X 1 0 0 This study 10: 1317GrA W438X 1 0 0 This study 11: 1411GrA E471K 1 0 0 Lewis et al. (1999) 12: 1622TrC L541P 21a 1a 0 Rozet et al. (1998), Fishman et al. (1999), Lewis et al. (1999), Maugeri et al. (1999) 1715GrA R572Q 1a 0 0 Lewis et al. (1999) 13: 1819GrA G607R 1 0 0 This study 1903CrA Q635K 2a 0 0 This study 1903CrT Q635X 1 0 0 This study IVS13ϩ1GrA Splice 2 0 0 This study 14: 1957CrT R653C 1 0 0 This study 1988GrA W663X 1 0 0 This study 2041CrT R681X 4 0 0 Maugeri et al. (1999) 15: 2291GrA C764Y 1 0 0 This study 2292delT Frameshift 1a 0 0 This study 2295TrG S765R 1a 0 0 This study 16: 2564GrA W855X 1 0 0 Nasonkin et al. (1998) 17: 2588GrC Spliceb 17a 6 5 Allikmets et al. (1997a), Cremers et al. (1998), Lewis et al. (1999), Maugeri et al. (1999), Papaioannou et al. (2000) 18: 2701ArG T901A 0 2 0 This study 2741ArG H914A 0 0 1 This study 19: 2876CrT T959I 1 0 0 This study 20: IVS20ϩ5GrA Splice 1 0 0 This study 21: 3106GrA E1036K 1a 0 0 Nasonkin et al. (1998) 3113CrT A1038V 26a 4a 1 Allikmets et al. (1997a), Cremers et al. (1998), Rozet et al. (1998), Fishman et al. (1999), Lewis et al. (1999), Maugeri et al. (1999) T3187TrC S1063P 1 0 0 This study (Continued) 805 Table 2 Continued EXON AND NUCLEOTIDE CHANGE EFFECT NO. OF ALLELES REFERENCE(S) STGD (288) AMD (400) Control (440) 22: 3292CrT R1097C 1 0 0 This study 3322CrT R1108C 4 0 0 Rozet et al. (1998), Fishman et al. (1999), Lewis et al. (1999) 24: 3528insTGCA Frameshift 1 0 0 This study 25: 3808GrT E1270X 1 0 0 This study 27: 3898CrT R1300X 1 0 0 This study 28: IVS28ϩ5GrA Splice 1 0 0 This study 4139CrT P1380L 1 0 0 Lewis et al. (1999) 4195GrA E1399K 2 0 0 This study 4234CrT Q1412X 4 0 0 Maugeri et al. (1999) 29: 4289TrC L1430P 2 0 0 This study 4318TrG F1440V 1 0 0 This study 4328GrA R1443H 1 0 0 This study 30: 4457CrT P1486L 1 0 0 Lewis et al. (1999) 4463GrA C1488Y 1 0 0 This study 31: 4610CrT T1537M 1 0 0 This study 35: IVS35ϩ2TrA Splice 1 0 0 This study 36: 5065TrC S1689P 1 0 0 This study 5114GrT R1705L 1 0 0 This study IVS36ϩ1GrA Splice 1 0 0 This study 37: 5198TrC M1733T 0 0 1 This study 5242GrA G1748R 1 0 0 This study 5248CrT Q1750X 1 0 0 This study 5288TrC L1763P 1 0 0 This study 38: IVS38ϩ1GrA Splice 1 0 0 This study 40: 5653GrA E1885K 1 0 0 This study 5693GrA R1898H 5 2 1 Allikmets et al. (1997b), Lewis et al. (1999) IVS40ϩ5GrA Splice 8a 0 0 Cremers et al. (1998), Lewis et al. (1999), Maugeri et al. (1999) 42: 5882GrA G1961E 34 4 2 Allikmets et al. (1997b), Fishman et al. (1999), Lewis et al. (1999), Maugeri et al. (1999) 43: 5917delG Frameshift 3 0 0 This study 5923GrC G1975R 1 0 0 This study 5929GrA G1977S 1 0 0 Rozet et al. (1998), Lewis et al. (1999) 45: 6229CrG R2077G 1 0 0 This study 6229CrT R2077W 1 0 0 Allikmets et al. (1997a), Fishman et al. (1999), Lewis et al. (1999) 48: 6609CrA Y2203X 2 0 0 This study 6647GrT A2216V 0 0 1 This study a Mutation pairs occurring on a single haplotype. Login to comment
90 In the group with AMD, 400 chromosomes were studied and 19 mutations were identified, with L541P and A1038V occurring on a single haplotype in one patient (AMD43). Login to comment
111 Likewise, for the intron 28 alteration, a spliced product Table 5 Patients with STGD Who Have Two Identified Disease Alleles AGE AT ONSET AND PATIENT MUTATION SEGREGATION IN FAMILY a Allele 1 Allele 2 5-9 years: STGD17 Q1412X R2077W Yes STGD88 G65E G1961E NA STGD93 G1961E G1961E Yes STGD99 L541P-A1038V G1961E Yes STGD100 L541P-A1038V IVS40ϩ5GrA Yes STGD108 Y362X IVS40ϩ5GrA Yes STGD109 L541P-A1038V W855X Yes STGD139b 5917delG 5917delG Yes STGD167 C1488Y IVS40ϩ5GrA Yes 10-14 years: STGD21 R681X R1898H NA STGD37 L541P-A1038V L541P-A1038V Yes STGD47/164 IVS13ϩ1GrA 2588GrC Yes STGD50 2588GrC A1038V NA STGD70 2588GrC IVS40ϩ5GrA NA STGD82 L541P-A1038V S1063P Yes STGD87 2588GrC Q1750X Yes STGD98 R212C T959I Yes STGD102 R572Q-2588GrC IVS35ϩ2TrA Yes STGD107 C764Y 3528ins4 Yes STGD120 L1430P L1430P NA STGD121 R1300X IVS40ϩ5GrA Yes STGD156 R1108C G1961E NA STGD159 R1108C Q1412X Yes STGD171 L541P-A1038V G1961E NA 15-19 years: STGD34 G768T G1961E Yes STGD39 L541P-A1038V R1443H NA STGD40/163 2588GrC E1885K Yes STGD45 E1399K G1977S Yes STGD59 R1898H G1975R NA STGD67 P68L S1689P Yes STGD75 Q635K IVS40ϩ5GrA Yes STGD111 2292delT-S765R G1961E Yes STGD114 Y2203X G1961E Yes STGD138 IVS13ϩ1GA 2588GrC Yes 20-24 years: STGD41 R681X G1961E Yes STGD63 A60T R1898H NA STGD86 296insA G1961E Yes STGD91 L541P-A1038V A1038V NA STGD113 L541P-A1038V 2588GrC Yes STGD118b IVS20ϩ5GrA G1961E Yes STGD119 L541P-A1038V G1961E Yes STGD122 L541P-A1038V G1961E Yes STGD135 W663X G1961E NA STGD147 IVS36ϩ1GrA G1961E Yes STGD168 L541P-A1038V G1961E NA 25-29 years: STGD62 G607R G1961E NA STGD71 296insA A1038V Yes STGD78 2588GrC Q1412X Yes STGD103 2588GrC IVS20ϩ5GrA Yes STGD116 L541P-A1038V G1961E Yes STGD139bb G1961E 5917delG Yes у30 years: STGD38 E471K G1961E Yes STGD68 E1399K G1961E Yes STGD69 L541P-A1038V 2588GrC NA STGD95 F1440V G1748R Yes STGD134 C230S G1961E NA STGD144 2588GrC R1705L NA STGD148 R1097C Y2203X NA STGD170 L541P-A1038V 2588GrC NA a NA p not applicable. Login to comment
149 Although the majority of mutations are rare, found in only one or two families, three disease alleles (2588GrC, L541P-A1038V, and G1961E) are present at high frequencies in the German population. Login to comment
152 The second-most-frequent allele is a complex allele, with A1038V occurring on the same haplotype as L541P (21/166 [12.7%]). Login to comment
153 Although the A1038V mutation is commonly reported in the literature, the L541P-A1038V complex allele has been reported only five times (Rozet et al. 1998; Fishman et al. 1999; Lewis et al. 1999; Maugeri et al. 1999). Login to comment
156 These three alterations, in combination with five others (R681X, A1038V as noncomplex allele, R1108C, Q1412X, R1898H, and IVS40ϩ5GrA), account for 61.4% of the detectable disease chromosomes in the German patients with STGD. Login to comment
172 On the contrary, specific mutations are associated with highly variable ages at onset; for example, compound heterozygosity for the complex allele L541P-A1038V and G1961E was found in patients with age at onset of 9-25 years (table 5). Login to comment
189 The findings in this study point to additional variants (2588GrC, A1038V, and R1898H) that are present in reasonable frequencies in the German population and that may be worthwhile candidates for further extended analyses in large-scale international efforts. Login to comment

[hide] Mutations in the ABCA4 (ABCR) gene are the major c... Am J Hum Genet. 2000 Oct;67(4):960-6. Epub 2000 Aug 24. Maugeri A, Klevering BJ, Rohrschneider K, Blankenagel A, Brunner HG, Deutman AF, Hoyng CB, Cremers FP
Mutations in the ABCA4 (ABCR) gene are the major cause of autosomal recessive cone-rod dystrophy.
Am J Hum Genet. 2000 Oct;67(4):960-6. Epub 2000 Aug 24., [PMID:10958761]

Abstract [show]
The photoreceptor cell-specific ATP-binding cassette transporter gene (ABCA4; previously denoted "ABCR") is mutated, in most patients, with autosomal recessive (AR) Stargardt disease (STGD1) or fundus flavimaculatus (FFM). In addition, a few cases with AR retinitis pigmentosa (RP) and AR cone-rod dystrophy (CRD) have been found to have ABCA4 mutations. To evaluate the importance of the ABCA4 gene as a cause of AR CRD, we selected 5 patients with AR CRD and 15 patients from Germany and The Netherlands with isolated CRD. Single-strand conformation-polymorphism analysis and sequencing revealed 19 ABCA4 mutations in 13 (65%) of 20 patients. In six patients, mutations were identified in both ABCA4 alleles; in seven patients, mutations were detected in one allele. One complex ABCA4 allele (L541P;A1038V) was found exclusively in German patients with CRD; one patient carried this complex allele homozygously, and five others were compound heterozygous. These findings suggest that mutations in the ABCA4 gene are the major cause of AR CRD. A primary role of the ABCA4 gene in STGD1/FFM and AR CRD, together with the gene's involvement in an as-yet-unknown proportion of cases with AR RP, strengthens the idea that mutations in the ABCA4 gene could be the most frequent cause of inherited retinal dystrophy in humans.

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107 The ABCA4 allele carrying only the A1038V mutation is one of the most frequent alleles in patients with STGD1 in the United States (15/150) (Lewis et al. 1999). Login to comment

[hide] New ABCR mutations and clinical phenotype in Itali... Invest Ophthalmol Vis Sci. 2000 Mar;41(3):892-7. Simonelli F, Testa F, de Crecchio G, Rinaldi E, Hutchinson A, Atkinson A, Dean M, D'Urso M, Allikmets R
New ABCR mutations and clinical phenotype in Italian patients with Stargardt disease.
Invest Ophthalmol Vis Sci. 2000 Mar;41(3):892-7., [PMID:10711710]

Abstract [show]
PURPOSE: To assess the mutation spectrum in the ABCR gene and clinical phenotypes in Italian families with autosomal recessive Stargardt disease (STGD1) and fundus flavimaculatus (FFM). METHODS: Eleven families from southern Italy, including 18 patients with diagnoses of STGD1, were clinically examined. Ophthalmologic examination included kinetic perimetry, electrophysiological studies, and fluorescein angiography. DNA samples of the affected individuals and their family members were analyzed for variants in all 50 exons of the ABCR gene by a combination of single-strand conformation polymorphism analysis and direct sequencing techniques. RESULTS: TenABCR variants were identified in 16 (73%) of 22 mutant alleles of patients with STGD1. Five mutations of 10 that were found had not been previously described. The majority of variants represent missense amino acid substitutions, and all mutant alleles cosegregate with the disease in the respective families. These ABCR variants were not detected in 170 unaffected control individuals (340 chromosomes) of Italian origin. Clinical evaluation of these families affected by STGD1 showed an unusually high frequency of early age-related macular degeneration (AMD) in parents of patients with STGD1 (8/22; 36%), consistent with the hypothesis that some heterozygous ABCR mutations enhance susceptibility to AMD. CONCLUSIONS: Patients from southern Italy with Stargardt disease show extensive allelic heterogeneity of the ABCR gene, concordant with previous observations in patients with STGD1 from different ethnic groups. Half the mutations identified in this study had not been previously described in patients with STGD1. Screening of increasingly large numbers of patients would help to determine whether this can be explained by ethnic differences, or is an indicator of extensive allelic heterogeneity of ABCR in STGD1 and other eye diseases. In 6 (55%) of 11 families, the first-degree relatives of patients with STGD1 were diagnosed with early AMD, supporting the previous observation that some STGD1 alleles are also associated with AMD.

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55 Clinical Characteristics and Segregation of Mutations in 11 Italian STGD/FFM Pedigrees Pedigree Patients Age Age of Onset Visual Acuity Diagnosis Allele 1 Allele 2 431 431 S 18 10 20/200 STGD R212C R212C 433 D 29 8 20/200 STGD R212C R212C 432 F 63 10 LE 20/40RE LP High myopia with macular involvement R212C R212H(p) 858 Gm 87 10 LP High myopia with macular involvement wt R212H(p) 774 M 60 58 20/25 Pigmentary abnormalities and drusen R212C wt 260 D 41 35 20/200 STGD 250ƒCAAA G1961E 759 S 39 38 20/100 STGD 250ƒCAAA G1961E 760 M 60 57 20/40 Pigmentary abnormalities and drusen wt G1961E 761 Gs 20/20 Normal wt G1961E 762 Gs 20/20 Normal 250ƒCAAA wt 631 631 S 18 3 20/200 STGD / FFM 5018 ϩ 2T 3 C 5018 ϩ 2T 3 C 777 F 59 58 20/20 Soft distinct drusen 5018 ϩ 2T 3 C wt 779 M 52 50 20/20 Hard distinct drusen 5018 ϩ 2T 3 C wt 624 624 D 40 18 20/200 STGD R1640Q G1961E 625 S 36 20 20/200 STGD R1640Q G1961E 834 M 74 20/20 Normal R1640Q wt 636 636 S 22 15 20/400 STGD / FFM E1087K G1961E 778 M 43 43 20/20 Hard distinct drusen wt G1961E 632 632 D 24 8 20/200 STGD / FFM 250ƒCAAA V767D 628 628 S 27 18 20/200 STGD T897I N/D 4 F 63 20/20 Normal wt N/D 5 M 62 62 20/20 Pigmentary abnormalities and drusen T897I N/D 633 633 D 12 8 20/400 STGD / FFM A1038V N/D 776 S 15 20/20 Normal A1038V N/D 634 D 20 10 20/400 STGD / FFM A1038V N/D 3 F 60 60 20/20 Pigmentary abnormalities and drusen wt N/D 2 M 49 20/20 Normal A1038V N/D 615 615 S 22 8 20/200 STGD / FFM 5018 ϩ 2T 3 C N/D 616 D 23 10 20/200 STGD / FFM 5018 ϩ 2T 3 C N/D 764 D 25 20/20 Normal 5018 ϩ 2T 3 C N/D 763 F 60 20/20 Normal 5018 ϩ 2T 3 C N/D 765 M 55 55 20/20 Pigmentary abnormalities and drusen wt N/D 629 629 D 23 10 STGD / FFM E1399K N/D 622 627 D 47 12 20/400 STGD N/D N/D 622 D 35 8 20/400 STGD / FFM N/D N/D 623 C 19 10 20/200 STGD / FFM S, son; D, daughter; F, father; M, mother; C, cousin; Gm, grandmother; Gs, grandson; (p), polymorphism; wt, wild type; N/D, not determined. Login to comment

[hide] Analysis of the Stargardt disease gene (ABCR) in a... Ophthalmology. 1999 Aug;106(8):1531-6. De La Paz MA, Guy VK, Abou-Donia S, Heinis R, Bracken B, Vance JM, Gilbert JR, Gass JD, Haines JL, Pericak-Vance MA
Analysis of the Stargardt disease gene (ABCR) in age-related macular degeneration.
Ophthalmology. 1999 Aug;106(8):1531-6., [PMID:10442900]

Abstract [show]
PURPOSE: Age-related macular degeneration (AMD) is a complex genetic disorder and the leading cause of severe vision loss in the elderly. The Stargardt disease gene (ABCR) has been proposed as a major genetic risk factor in AMD. The purpose of this study was to evaluate the authors' AMD population for the specific ABCR variants proposed previously as genetic risk factors for AMD. METHODS: The authors screened their AMD population (159 familial cases from 112 multiplex families and 53 sporadic cases) and 56 racially matched individuals with no known history of AMD from the same clinic population for evidence of the ABCR variants. Grading of disease severity was performed according to a standard protocol. Patients with extensive intermediate drusen or large soft drusen, drusenoid retinal pigment epithelial (RPE) detachments, geographic atrophy of the RPE, or evidence of exudative maculopathy were considered affected. Analysis for variants was performed by polymerase chain reaction amplification of individual exons of the ABCR gene with flanking primers and a combination of single-strand conformation polymorphism, heteroduplex analysis, and high-performance liquid chromatography. All abnormal conformers detected using these techniques were characterized by direct sequencing. RESULTS: The authors identified only two of the previously reported variants in their study population. Both variants occurred in sporadic cases, and none was found in familial cases or the randomly selected population. In addition, the authors identified several newly described polymorphisms and variants in both the AMD and control populations. CONCLUSIONS: Based on these initial findings, the authors suggest that ABCR is not a major genetic risk factor for AMD in their study population. Additional genetic studies are needed to more fully evaluate the role of ABCR in AMD.

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93 A second variant was identified (A1038V) in an unaffected member of an AMD family and in no other individuals. Login to comment

[hide] Variation of clinical expression in patients with ... Arch Ophthalmol. 1999 Apr;117(4):504-10. Fishman GA, Stone EM, Grover S, Derlacki DJ, Haines HL, Hockey RR
Variation of clinical expression in patients with Stargardt dystrophy and sequence variations in the ABCR gene.
Arch Ophthalmol. 1999 Apr;117(4):504-10., [PMID:10206579]

Abstract [show]
OBJECTIVE: To report the spectrum of ophthalmic findings in patients with Stargardt dystrophy or fundus flavimaculatus who have a specific sequence variation in the ABCR gene. PATIENTS: Twenty-nine patients with Stargardt dystrophy or fundus flavimaculatus from different pedigrees were identified with possible disease-causing sequence variations in the ABCR gene from a group of 66 patients who were screened for sequence variations in this gene. METHODS: Patients underwent a routine ocular examination, including slitlamp biomicroscopy and a dilated fundus examination. Fluorescein angiography was performed on 22 patients, and electroretinographic measurements were obtained on 24 of 29 patients. Kinetic visual fields were measured with a Goldmann perimeter in 26 patients. Single-strand conformation polymorphism analysis and DNA sequencing were used to identify variations in coding sequences of the ABCR gene. RESULTS: Three clinical phenotypes were observed among these 29 patients. In phenotype I, 9 of 12 patients had a sequence change in exon 42 of the ABCR gene in which the amino acid glutamic acid was substituted for glycine (Gly1961Glu). In only 4 of these 9 patients was a second possible disease-causing mutation found on the other ABCR allele. In addition to an atrophic-appearing macular lesion, phenotype I was characterized by localized perifoveal yellowish white flecks, the absence of a dark choroid, and normal electroretinographic amplitudes. Phenotype II consisted of 10 patients who showed a dark choroid and more diffuse yellowish white flecks in the fundus. None exhibited the Gly1961Glu change. Phenotype III consisted of 7 patients who showed extensive atrophic-appearing changes of the retinal pigment epithelium. Electroretinographic cone and rod amplitudes were reduced. One patient showed the Gly1961Glu change. CONCLUSIONS: A wide variation in clinical phenotype can occur in patients with sequence changes in the ABCR gene. In individual patients, a certain phenotype seems to be associated with the presence of a Gly1961Glu change in exon 42 of the ABCR gene. CLINICAL RELEVANCE: The identification of correlations between specific mutations in the ABCR gene and clinical phenotypes will better facilitate the counseling of patients on their visual prognosis. This information will also likely be important for future therapeutic trials in patients with Stargardt dystrophy.

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70 Clinical Features of Patients With ABCR Gene Mutations* Patient No./ Sex/Age, y Clinical Phenotype Vision Silent Choroid Central Scotoma MutationOD OS 1/M/19 I 20/200 20/200 ND + Thr300Asn, exon 8 2/M/44 I 20/25 20/15 - + Cys1488Arg, exon 30 3/M/35 I 20/100 20/100 ND + Gly1961Glu, exon 42 Cys2150Tyr, exon 47 4/M/44 I 20/200 20/200 - + Gly1961Glu, exon 42 5/F/28 I 20/80 20/100 - + Gly1961Glu, exon 42 Gly65Glu, exon 3 6/M/36 I 20/25 20/200 - + Gly1961Glu, exon 42 Arg2077Trp, exon 45 7/F/44 I 20/200 20/200 - + Gly1961Glu, exon 42 8/M/41 I 20/200 20/200 - + Gly1961Glu, exon 42 9/F/32 I 20/25 20/30 - + Gly1961Glu, exon 42 10/F/36 I 20/50 20/200 - + Gly1961Glu, exon 42 11/M/31 I 20/200 20/200 - + Gly1961Glu, exon 42 Ala1038Val, exon 21 Leu541Pro, exon 12 12/M/35 I 20/200 20/200 - + Arg2107His, exon 46 Leu1729Pro, exon 36 13/M/22 II 20/200 20/200 + + 1bp del (g), codon 448, exon 10 14/F/9 II 20/200 20/40 ND + 9bp del, codon 1760/1761, exon 37 1bp ins (c), codon 1513, exon 30 15/M/19 II 10/120 10/160 + + 1bp ins (c), codon 1513, exon 30 Ala60Val, exon 3 16/M/25 II 20/200 20/200 + ND Ser974Pro, exon 20 17/F/12 II 20/200 20/200 ND + 2884 del (c), exon 19 18/F/73 II 20/30 20/25 + Paracentral scotoma 5bp del, codon 505, exon 11 19/F/35 II 10/160 10/120 ND + Val849Ala, exon 16 20/F/48 II 20/400 20/400 + +; Mild peripheral restriction Val849Ala, exon 16 Arg2107His, exon 46 21/M/54 II 20/200 20/200 + + Arg2030stop, exon 44 22/M/28 II 20/400 20/400 + + His2128Arg, exon 46 23/F/34 III 10/400 10/225 Diffuse hyperfluorescence ND Arg2038Trp, exon 44 24/F/53 III 10/700 10/600 Diffuse hyperfluorescence and notable choroidal atrophy + Arg1108Cys, exon 22 25/F/54 III 10/350 3/350 Diffuse hyperfluorescence +; Mild concentric restriction Tyr1652Asp, exon 35 Arg2107His, exon 46 26/M/57 III 20/50 20/80 ND ND Splice donor GϾA, exon 24 27/F/65 III 1/225 1/225 Diffuse choroidal atrophy Temporal islands Gly1961Glu, exon 42 frameshift del, codons 1620-1622, exon 35† 28/M/32 III 20/400 20/400 Diffuse hyperfluorescence +; Peripheral restriction Ala1038Val, exon 21 Leu541Pro, exon 12 Donor splice, exon 30 29/M/46 III 10/225 10/225 ND +; Peripheral restriction Trp1408Leu, exon 28 Ser206Arg, exon 6 Arg2107His, exon 46 *M indicates male; F, female; ND, angiography or visual field testing not done; +, present; and -, absent. Login to comment

[hide] Genotype/Phenotype analysis of a photoreceptor-spe... Am J Hum Genet. 1999 Feb;64(2):422-34. Lewis RA, Shroyer NF, Singh N, Allikmets R, Hutchinson A, Li Y, Lupski JR, Leppert M, Dean M
Genotype/Phenotype analysis of a photoreceptor-specific ATP-binding cassette transporter gene, ABCR, in Stargardt disease.
Am J Hum Genet. 1999 Feb;64(2):422-34., [PMID:9973280]

Abstract [show]
Mutation scanning and direct DNA sequencing of all 50 exons of ABCR were completed for 150 families segregating recessive Stargardt disease (STGD1). ABCR variations were identified in 173 (57%) disease chromosomes, the majority of which represent missense amino acid substitutions. These ABCR variants were not found in 220 unaffected control individuals (440 chromosomes) but do cosegregate with the disease in these families with STGD1, and many occur in conserved functional domains. Missense amino acid substitutions located in the amino terminal one-third of the protein appear to be associated with earlier onset of the disease and may represent misfolding alleles. The two most common mutant alleles, G1961E and A1038V, each identified in 16 of 173 disease chromosomes, composed 18.5% of mutations identified. G1961E has been associated previously, at a statistically significant level in the heterozygous state, with age-related macular degeneration (AMD). Clinical evaluation of these 150 families with STGD1 revealed a high frequency of AMD in first- and second-degree relatives. These findings support the hypothesis that compound heterozygous ABCR mutations are responsible for STGD1 and that some heterozygous ABCR mutations may enhance susceptibility to AMD.

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2 The two most common mutant alleles, G1961E and A1038V, each identified in 16 of 173 disease chromosomes, composed 18.5% of mutations identified. Login to comment
76 2 0071GrA R24H 1 19 2894ArG N965S 3 36 5196ϩ1GrA Splice 2 3 0161GrA C54Y 1 21 3113CrT A1038V 16 5196ϩ2TrC Splice 1 0179CrT A60V 1 22 3211insGT FS 1 37 5281del9 PAL1761del 1 0203CrG P68R 1 3212CrT S1071L 1 38 5459GrC R1820P 1 0223TrG C75G 1 3215TrC V1072A 1 39 5512CrT H1838Y 1 6 0634CrT R212C 1 3259GrA E1087K 1 5527CrT R1843W 1 0664del13 FS 1 3322CrT R1108C 6 40 5585-1GrA Splice 1 0746ArG D249G 1 23 3364GrA E1122K 1 5657GrA G1886E 1 8 1007CrG S336C 1 3385GrT R1129C 1 5693GrA R1898H 4 1018TrG Y340D 1 3386GrT R1129L 2 5714ϩ5GrA Splice 8 11 1411GrA E471K 1 24 3602TrG L1201R 1 42 5882GrA G1961E 16 12 1569TrG D523E 1 25 3610GrA D1204N 1 5898ϩ1GrT Splice 3 1622TrC L541P 1 28 4139CrT P1380L 4 43 5908CrT L1970F 1 1715GrA R572Q 2 4216CrT H1406Y 1 5929GrA G1977S 1 1715GrC R572P 1 4222TrC W1408R 4 6005ϩ1GrT Splice 1 13 1804CrT R602W 1 4232insTATG FS 1 44 6079CrT L2027F 11 1822TrA F608I 2 4253ϩ5GrT Splice 1 6088CrT R2030X 1 1917CrA Y639X 1 29 4297GrA V1433I 1 6089GrA R2030Q 1 1933GrA D645N 1 4316GrA G1439D 2 6112CrT R2038W 1 14 2005delAT FS 1 4319TrC F1440S 1 45 6148GrC V2050L 2 2090GrA W697X 1 4346GrA W1449X 1 6166ArT K2056X 1 2160ϩ1GrC Splice 1 30a 4462TrC C1488R 2 6229CrT R2077W 1 16 2453GrA G818E 1 4457CrT P1486L 1 46 6286GrA E2096K 1 2461TrA W821R 1 30b 4469GrA C1490Y 3 6316CrT R2106C 1 2536GrC D846H 1 4539ϩ1GrT Splice 1 47 6391GrA E2131K 1 2552GrC G851D 1 31 4577CrT T1526M 7 6415CrT R2139W 1 17 2588GrC G863A 11 4594GrA D1532N 3 6445CrT R2149X 1 19 2791GrA V931M 2 35 4947delC FS 1 48 6543del36 1181del12 1 2827CrT R943W 1 36 5041del15 VVAIC1681del 2 6709insG FS 1 2884delC FS 1 5087GrA S1696N 1 NOTE.-FS ϭ frameshift. Login to comment
101 For the double-mutant chromosomes in the compound heterozygous families (AR31: Y340D and R572Q; AR106: E471K and E2131K; AR128: R572Q and G863A; and AR189: L541P and A1038V) and in those families in which the second disease chromosome was not identified (AR215: H1406Y and V2050L; AR264: D1204N and L2027F; AR254: D249G and R1898H; AR265: G863A and R1898H; AR285: 2714ϩ5GrA and 2884delC; and AR305: G863A and R1898H), in three cases (AR128, AR265, and AR305) each mutation on the double-mutant chromosome had been identified independently as disease causing in other, unrelated families with STGD1 (table 1). Login to comment
110 Seven mutant alleles, including six missense amino acid substitutions and one splice-site mutation (G863A, A1038V, R1108C, T1526M, G1961E, L2027F, and 5714ϩ5GrA) accounted for 41% of the disease-causing mutations identified in this cohort. Login to comment
111 In three instances, identical codons were affected by different base-pair substitutions, yielding different predicted missense amino acid substitutions (R572Q and R572P; R1129C and R1129L) or a missense substitution and a stop codon (R2030Q and R2030X). Login to comment
139 Different families with the same combination of alleles (e.g., AR326 and AR391, both with genotype L2027F/T1526M; AR376 and AR393, both with genotype A1038V/R1108C) usually have similar ages at onset, as was shown for Figure 4 Pedigree AR33, a family with STGD that manifests a pseudodominant inheritance pattern. Login to comment
146 However, variation in self-reported age at onset, even by 11 decade, was noted for two families with identical ABCR compound heterozygous genotypes (age 8 years for family AR417 and age 20 years for family AR274, each with genotype G1961E/A1038V), suggesting either modifier alleles or environmental factors affecting disease expression or different sensitivity to reported age at onset. Login to comment
178 Table 2 ABCR Allelic Series MUTATION(S) PEDIGREE AGE AT ONSET (YEARS) MEAN AGE AT ONSET ‫ע‬ SD (YEARS)Allele 1 Allele 2 G863A Y340D, R772Q AR31 8 19.6 ‫ע‬ 12.7 51961GrA AR307 10 A1038V AR290 16 5714ϩ5GrA AR314 25 5898ϩ1GrT AR336 39 A1038V R572P AR321 6 12.5 ‫ע‬ 6.9 S1071L AR358 6 L1970F AR428 6 5196ϩ2TrC AR71 7 G1961E AR417 8 L2027F AR181 9 R1898H AR78 14 G863A AR290 16 G1961E AR274 20 R1108C AR393 20 R1108C AR376 25 P1380L W1408R AR341 6 8.2 ‫ע‬ 1.5 E1122K AR534 8 2005delAT AR357 8 D1532N AR423 9 W821R AR534 10 G1961E A1038V AR417 8 14.3 ‫ע‬ 4.5 C75G AR427 12 C1490Y AR370 13 2160ϩ1GrC AR218 14 4253ϩ5GrT AR373 19 A1038V AR274 20 L2027F R602W AR88 9 13.0 ‫ע‬ 5.5 A1038V AR181 9 R2149X AR263 9 T1526M AR326 19 T1526M AR391 19 (70%) had onset in the first 2 decades of life, but 11 (16%) had onset in the 3d decade and 6 (9%) in the 4th decade. Login to comment
77 2 0071GrA R24H 1 19 2894ArG N965S 3 36 5196af9;1GrA Splice 2 3 0161GrA C54Y 1 21 3113CrT A1038V 16 5196af9;2TrC Splice 1 0179CrT A60V 1 22 3211insGT FS 1 37 5281del9 PAL1761del 1 0203CrG P68R 1 3212CrT S1071L 1 38 5459GrC R1820P 1 0223TrG C75G 1 3215TrC V1072A 1 39 5512CrT H1838Y 1 6 0634CrT R212C 1 3259GrA E1087K 1 5527CrT R1843W 1 0664del13 FS 1 3322CrT R1108C 6 40 5585afa;1GrA Splice 1 0746ArG D249G 1 23 3364GrA E1122K 1 5657GrA G1886E 1 8 1007CrG S336C 1 3385GrT R1129C 1 5693GrA R1898H 4 1018TrG Y340D 1 3386GrT R1129L 2 5714af9;5GrA Splice 8 11 1411GrA E471K 1 24 3602TrG L1201R 1 42 5882GrA G1961E 16 12 1569TrG D523E 1 25 3610GrA D1204N 1 5898af9;1GrT Splice 3 1622TrC L541P 1 28 4139CrT P1380L 4 43 5908CrT L1970F 1 1715GrA R572Q 2 4216CrT H1406Y 1 5929GrA G1977S 1 1715GrC R572P 1 4222TrC W1408R 4 6005af9;1GrT Splice 1 13 1804CrT R602W 1 4232insTATG FS 1 44 6079CrT L2027F 11 1822TrA F608I 2 4253af9;5GrT Splice 1 6088CrT R2030X 1 1917CrA Y639X 1 29 4297GrA V1433I 1 6089GrA R2030Q 1 1933GrA D645N 1 4316GrA G1439D 2 6112CrT R2038W 1 14 2005delAT FS 1 4319TrC F1440S 1 45 6148GrC V2050L 2 2090GrA W697X 1 4346GrA W1449X 1 6166ArT K2056X 1 2160af9;1GrC Splice 1 30a 4462TrC C1488R 2 6229CrT R2077W 1 16 2453GrA G818E 1 4457CrT P1486L 1 46 6286GrA E2096K 1 2461TrA W821R 1 30b 4469GrA C1490Y 3 6316CrT R2106C 1 2536GrC D846H 1 4539af9;1GrT Splice 1 47 6391GrA E2131K 1 2552GrC G851D 1 31 4577CrT T1526M 7 6415CrT R2139W 1 17 2588GrC G863A 11 4594GrA D1532N 3 6445CrT R2149X 1 19 2791GrA V931M 2 35 4947delC FS 1 48 6543del36 1181del12 1 2827CrT R943W 1 36 5041del15 VVAIC1681del 2 6709insG FS 1 2884delC FS 1 5087GrA S1696N 1 NOTE.-FS afd; frameshift. Login to comment
102 For the double-mutant chromosomes in the compound heterozygous families (AR31: Y340D and R572Q; AR106: E471K and E2131K; AR128: R572Q and G863A; and AR189: L541P and A1038V) and in those families in which the second disease chromosome was not identified (AR215: H1406Y and V2050L; AR264: D1204N and L2027F; AR254: D249G and R1898H; AR265: G863A and R1898H; AR285: 2714af9;5GrA and 2884delC; and AR305: G863A and R1898H), in three cases (AR128, AR265, and AR305) each mutation on the double-mutant chromosome had been identified independently as disease causing in other, unrelated families with STGD1 (table 1). Login to comment
140 Different families with the same combination of alleles (e.g., AR326 and AR391, both with genotype L2027F/T1526M; AR376 and AR393, both with genotype A1038V/R1108C) usually have similar ages at onset, as was shown for Figure 4 Pedigree AR33, a family with STGD that manifests a pseudodominant inheritance pattern. Login to comment
147 However, variation in self-reported age at onset, even by 11 decade, was noted for two families with identical ABCR compound heterozygous genotypes (age 8 years for family AR417 and age 20 years for family AR274, each with genotype G1961E/A1038V), suggesting either modifier alleles or environmental factors affecting disease expression or different sensitivity to reported age at onset. Login to comment
179 Table 2 ABCR Allelic Series MUTATION(S) PEDIGREE AGE AT ONSET (YEARS) MEAN AGE AT ONSET cf2; SD (YEARS) Allele 1 Allele 2 G863A Y340D, R772Q AR31 8 19.6 cf2; 12.7 51961GrA AR307 10 A1038V AR290 16 5714af9;5GrA AR314 25 5898af9;1GrT AR336 39 A1038V R572P AR321 6 12.5 cf2; 6.9 S1071L AR358 6 L1970F AR428 6 5196af9;2TrC AR71 7 G1961E AR417 8 L2027F AR181 9 R1898H AR78 14 G863A AR290 16 G1961E AR274 20 R1108C AR393 20 R1108C AR376 25 P1380L W1408R AR341 6 8.2 cf2; 1.5 E1122K AR534 8 2005delAT AR357 8 D1532N AR423 9 W821R AR534 10 G1961E A1038V AR417 8 14.3 cf2; 4.5 C75G AR427 12 C1490Y AR370 13 2160af9;1GrC AR218 14 4253af9;5GrT AR373 19 A1038V AR274 20 L2027F R602W AR88 9 13.0 cf2; 5.5 A1038V AR181 9 R2149X AR263 9 T1526M AR326 19 T1526M AR391 19 (70%) had onset in the first 2 decades of life, but 11 (16%) had onset in the 3d decade and 6 (9%) in the 4th decade. Login to comment

[hide] Autosomal recessive retinitis pigmentosa and cone-... Hum Mol Genet. 1998 Mar;7(3):355-62. Cremers FP, van de Pol DJ, van Driel M, den Hollander AI, van Haren FJ, Knoers NV, Tijmes N, Bergen AA, Rohrschneider K, Blankenagel A, Pinckers AJ, Deutman AF, Hoyng CB
Autosomal recessive retinitis pigmentosa and cone-rod dystrophy caused by splice site mutations in the Stargardt's disease gene ABCR.
Hum Mol Genet. 1998 Mar;7(3):355-62., [PMID:9466990]

Abstract [show]
Ophthalmological and molecular genetic studies were performed in a consanguineous family with individuals showing either retinitis pigmentosa (RP) or cone-rod dystrophy (CRD). Assuming pseudodominant (recessive) inheritance of allelic defects, linkage analysis positioned the causal gene at 1p21-p13 (lod score 4.22), a genomic segment known to harbor the ABCR gene involved in Stargardt's disease (STGD) and age-related macular degeneration (AMD). We completed the exon-intron structure of the ABCR gene and detected a severe homozygous 5[prime] splice site mutation, IVS30+1G->T, in the four RP patients. The five CRD patients in this family are compound heterozygotes for the IVS30+1G->T mutation and a 5[prime] splice site mutation in intron 40 (IVS40+5G->A). Both splice site mutations were found heterozygously in two unrelated STGD patients, but not in 100 control individuals. In these patients the second mutation was either a missense mutation or unknown. Since thus far no STGD patients have been reported to carry two ABCR null alleles and taking into account that the RP phenotype is more severe than the STGD phenotype, we hypothesize that the intron 30 splice site mutation represents a true null allele. Since the intron 30 mutation is found heterozygously in the CRD patients, the IVS40+5G->A mutation probably renders the exon 40 5[prime] splice site partially functional. These results show that mutations in the ABCR gene not only result in STGD and AMD, but can also cause autosomal recessive RP and CRD. Since the heterozygote frequency for ABCR mutations is estimated at 0.02, mutations in ABCR might be an important cause of autosomal recessive and sporadic forms of RP and CRD.

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106 STGD patient 8439 carries a C!T transition at nucleotide position 3113, resulting in an Ala1038Val mutation in the predicted ABCR protein (Table 1). Login to comment
128 Genotype-phenotype comparison for the RP, CRD, STGD/FFM and AMD patients and a hypothetical correlation between ABCR activity and the observed phenotypes Patient Phenotype ABCR allele 1 ABCR allele 2 ABCR activity 7023 (V-3) RP IVS30+1G→T IVS30+1G→T - 7028 (IV-7) CRD IVS30+1G→T IVS40+5G→A +/- 7560 STGD IVS30+1G→T Gly863Ala + 7727 STGD IVS30+1G→T Unknown + 8439 STGD IVS40+5G→A Ala1038Val + 8272 STGD/FFM IVS40+5G→A Unknown + AMD Missense or null mutation (19) ++ Normal ++++ 3360 Figure . Login to comment
104 STGD patient 8439 carries a CT transition at nucleotide position 3113, resulting in an Ala1038Val mutation in the predicted ABCR protein (Table 1). Login to comment
125 Genotype-phenotype comparison for the RP, CRD, STGD/FFM and AMD patients and a hypothetical correlation between ABCR activity and the observed phenotypes Patient Phenotype ABCR allele 1 ABCR allele 2 ABCR activity 7023 (V-3) RP IVS30+1G࢐T IVS30+1G࢐T - 7028 (IV-7) CRD IVS30+1G࢐T IVS40+5G࢐A +/- 7560 STGD IVS30+1G࢐T Gly863Ala + 7727 STGD IVS30+1G࢐T Unknown + 8439 STGD IVS40+5G࢐A Ala1038Val + 8272 STGD/FFM IVS40+5G࢐A Unknown + AMD Missense or null mutation (19) ++ Normal ++++ Figure 5. Login to comment

[hide] Stargardt disease caused by a rare combination of ... Medicina (Kaunas). 2013;49(8):386-91. Serapinas D, Obrikyte V, Sakalauskas R
Stargardt disease caused by a rare combination of double homozygous mutations.
Medicina (Kaunas). 2013;49(8):386-91., [PMID:24509150]

Abstract [show]
Stargardt disease is a juvenile macular degeneration most often inherited in an autosomal recessive pattern, characterized by decreased vision in the first 2 decades of life. This report presents a clinical case of Stargardt disease: a 10-year-old female patient complained of blurry vision, and in a 4-year period, her visual acuity was reduced from OD=0.3 and OS=0.3 to OD=0.08 and OS=0.1, respectively. A genetic analysis revealed a rare combination of 2 homozygous recessive mutations in the ABCA4 gene, which caused Stargardt disease. The presence of different genetic mechanisms leading to a severe disease phenotype can challenge molecular geneticists, ophthalmologists, and genetic counselors.

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47 The analysis of the DNA testing results showed 2 mutations in the ABCA4 gene: a nucleotide substitution in exon 12 (c.1622T>C; L541P) and a nucleotide substitution in exon 21 (c.3113C>T; A1038V). Login to comment
60 Several studies have identified frequent ethnic group-specific ABCA4 alleles, such as the c.2588G>C variant resulting in a dual effect, p.G863A/delG863 as a founder mutation in Northern European patients with Stargardt disease, and a complex allele p.L541P/A1038V in the patients of the German origin who have both Stargardt disease and cone-rod dystrophy. Login to comment
64 Our presented mutations (L541P and A1038V) are not rare in Stargardt disease, but in this case, the disease was caused by a rare combination of double homozygous mutations. Login to comment
67 A1038V, a missense mutation, is reported as one of the most common mutations in the ABCA4 gene when is detected as a component of the complex allele L541P/A1038V. Login to comment
68 The complex allele demonstrates mislocalization and therefore reduced function of the ABCA4 protein, while the protein associated with A1038V alone does not mislocalize. Login to comment
69 A1038V is also pathogenic without L541P as it has a deleterious impact on ATPase by ABCA4 in vitro (13). Login to comment
46 The analysis of the DNA testing results showed 2 mutations in the ABCA4 gene: a nucleotide substitution in exon 12 (c.1622T>C; L541P) and a nucleotide substitution in exon 21 (c.3113C>T; A1038V). Login to comment
59 Several studies have identified frequent ethnic group-specific ABCA4 alleles, such as the c.2588G>C variant resulting in a dual effect, p.G863A/delG863 as a founder mutation in Northern European patients with Stargardt disease, and a complex allele p.L541P/A1038V in the patients of the German origin who have both Stargardt disease and cone-rod dystrophy. Login to comment
63 Our presented mutations (L541P and A1038V) are not rare in Stargardt disease, but in this case, the disease was caused by a rare combination of double homozygous mutations. Login to comment
66 A1038V, a missense mutation, is reported as one of the most common mutations in the ABCA4 gene when is detected as a component of the complex allele L541P/A1038V. Login to comment

[hide] Evaluation of the common variants of the ABCA4 gen... Int J Mol Med. 2008 Jun;21(6):715-20. Shastry BS
Evaluation of the common variants of the ABCA4 gene in families with Stargardt disease and autosomal recessive retinitis pigmentosa.
Int J Mol Med. 2008 Jun;21(6):715-20., [PMID:18506364]

Abstract [show]
Stargardt disease (STGD) is one of the most common autosomal recessive retinal dystrophies with an estimated incidence of one in 10,000. It affects the central retina (macula). Retinitis pigmentosa (RP) comprises a large and exceptionally heterogeneous group of hereditary disorders of the retina. It is caused by the loss of photoreceptors. The condition is a degenerative disorder characterized by retinal pigment deposits and has an estimated incidence of one in 4,000. Although, to date, 45 known loci have been identified, none of them independently account for a substantial portion of RP. Recently, the photoreceptor cell-specific ATP-binding cassette transporter (ABCA4) gene was found to be mutated in patients with STGD as well as autosomal recessive RP. In order to further understand the contribution of this gene to the susceptibility to STGD and RP, we analyzed three unrelated STGD families and one autosomal recessive RP family specifically for the more common variants (A1038V, G1961E, 2588G-->C, R943Q or 2828G-->A) in the ABCA4 gene. Our analyses employing standard techniques such as polymerase chain reaction, restriction fragment length polymorphism, and direct DNA sequencing of amplified products were able to identify one common variant (R943Q) in all three STGD families but not in the RP family. All three affected STGD individuals, however, were heterozygous for this variation, and this alteration did not segregate with the disease and was also present in the normal controls. Similar analysis of other common variants revealed no pathogenic mutations in the STGD and RP families. It is likely that the variant identified in this study represents a rare polymorphism (non-pathogenic). Although, at present we cannot eliminate the possibility of this gene as a candidate gene, future extensive studies on this as well as other candidate genes may uncover the susceptibility gene for these recessive forms of the disorders in these families.

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8 In order to further understand the contribution of this gene to the susceptibility to STGD and RP, we analyzed three unrelated STGD families and one autosomal recessive RP family specifically for the more common variants (A1038V, G1961E, 2588G&#a1;C, R943Q or 2828G&#a1;A) in the ABCA4 gene. Login to comment
49 To further extend the diagnostic and prognostic value of the molecular genetic study of STGD and to understand the genetic heterogeneity of RP, in this report we analyzed three unrelated STGD families and one AR RP family specifically for the more common variants (A1038V, G1961E, R943Q or 2828G&#a1;A and 2588G&#a1;C) of the ABCA4 gene which when mutated produce a broad spectrum of the retinal phenotypes including RP and age-related macular degeneration (AMD). Login to comment
79 The amplified product was subjected to restriction enzyme digestion with either 10 units of Alu I (2588G&#a1;C mutation in exon 17 of ABCA4 gene creates a site for Alu I), or Bse YI (A1038V mutation in exon 21 destroys a site for Bse YI), or Taq I (G1961E variation in exon 42 in ABCA4 creates a Taq I site), or Msp I (R943Q alteration in exon 19 destroys the Msp I site), or Nla III (Y402H mutation in exon 9 of the CFH gene creates a Nla III site) at 37da;C (Alu I, Bse YI, Msp I, Nla III) and 65da;C (Taq I) for 1 h. Login to comment
83 The finding that the variants A1038V (exon 21), G1961E (exon 42), 2588G&#a1;C (exon 17) and R943Q (exon 19) which is previously known as 2828G&#a1;A (4) are more common INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE 21: 715-720, 2008 717 Figure 1. Login to comment
99 Additionally, we failed to detect the other two alterations (A1038V and 2588G&#a1;C). Login to comment
109 Restriction digestion patterns of PCR-amplified products for variants 2588 G&#a1;C (A), A1038V (B), G1961E (C) and Y402H (D). Login to comment

[hide] Allelic and phenotypic heterogeneity in ABCA4 muta... Ophthalmic Genet. 2011 Sep;32(3):165-74. doi: 10.3109/13816810.2011.565397. Epub 2011 Apr 21. Burke TR, Tsang SH
Allelic and phenotypic heterogeneity in ABCA4 mutations.
Ophthalmic Genet. 2011 Sep;32(3):165-74. doi: 10.3109/13816810.2011.565397. Epub 2011 Apr 21., [PMID:21510770]

Abstract [show]
Since the discovery of the ABCA4 gene as the cause of autosomal recessive Stargardt disease/fundus flavimaculatus much has been written of the phenotypic variability in ABCA4 retinopathy. In this review the authors discuss the findings seen on examination and the disease features detected using various clinical tests. Important differential diagnoses are presented and unusual presentations of ABCA4 disease highlighted.

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7 The most common, L541P/A1038V, has been reported as a founder mutation in Hungaro-German populations.14,16,17 Furthermore "ethnic group-specific" ABCA4 alleles have been described in other populations also, C1490Y and R602W in South African patients,18 and N965S in a Danish population19 among others.20 In an attempt to explain the variability seen in ABCA4 retinal phenotypes and to correlate this with individual mutation effect, a model was proposed which correlated disease severity with residual ABCA4 function.14,21 Maugeri classified ABCA4 mutant alleles as "mild", "moderate", and "severe" based on the predicted effect of the mutation on the transport function of the protein, ie, the more severe the effect of the mutation on ABCA4 function, the more aggressive the disease phenotype. Login to comment

[hide] Analysis of the ABCA4 gene by next-generation sequ... Invest Ophthalmol Vis Sci. 2011 Oct 31;52(11):8479-87. doi: 10.1167/iovs.11-8182. Zernant J, Schubert C, Im KM, Burke T, Brown CM, Fishman GA, Tsang SH, Gouras P, Dean M, Allikmets R
Analysis of the ABCA4 gene by next-generation sequencing.
Invest Ophthalmol Vis Sci. 2011 Oct 31;52(11):8479-87. doi: 10.1167/iovs.11-8182., [PMID:21911583]

Abstract [show]
PURPOSE: To find all possible disease-associated variants in coding sequences of the ABCA4 gene in a large cohort of patients diagnosed with ABCA4-associated diseases. METHODS: One hundred sixty-eight patients who had been clinically diagnosed with Stargardt disease, cone-rod dystrophy, and other ABCA4-associated phenotypes were prescreened for mutations in ABCA4 with the ABCA4 microarray, resulting in finding 1 of 2 expected mutations in 111 patients and 0 of 2 mutations in 57 patients. The next-generation sequencing (NGS) strategy was applied to these patients to sequence the entire coding region and the splice sites of the ABCA4 gene. Identified new variants were confirmed or rejected by Sanger sequencing and analyzed for possible pathogenicity by in silico programs and, where possible, by segregation analyses. RESULTS: Sequencing was successful in 159 of 168 patients and identified the second disease-associated allele in 49 of 103 (~48%) of patients with one previously identified mutation. Among those with no mutations, both disease-associated alleles were detected in 4 of 56 patients, and one mutation was detected in 10 of 56 patients. The authors detected a total of 57 previously unknown, possibly pathogenic, variants: 29 missense, 4 nonsense, 9 small deletions and 15 splice-site-altering variants. Of these, 55 variants were deemed pathogenic by a combination of predictive methods and segregation analyses. CONCLUSIONS: Many mutations in the coding sequences of the ABCA4 gene are still unknown, and many possibly reside in noncoding regions of the ABCA4 locus. Although the ABCA4 array remains a good first-pass screening option, the NGS platform is a time- and cost-efficient tool for screening large cohorts.

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17 Several studies have identified frequent "ethnic group-specific" ABCA4 alleles, such as the c.2588Gb0e;C variant resulting in a dual effect, p.G863A/delG863, as a founder mutation in Northern European patients with STGD17 and a complex allele (two variants on the same chromosome), p.L541P/A1038V, in both STGD1 and CRD patients of German origin (Fig. 2B).3,8 Complex ABCA4 alleles are not uncommon in STGD1.9 In fact, they are detected in approximately 10% of all STGD patients.10 Allelic heterogeneity has substantially complicated genetic analyses of ABCA4-associated retinal disease. Login to comment
145 The best known example from this category in ABCA4 is the c.5461-10Tb0e;C variant in intron 38, which is the third most frequent variant (found in 7.1% of STGD1 patients) after the p.G1961E and p.L541P/A1038V mutations in our study. Login to comment

[hide] The clinical effect of homozygous ABCA4 alleles in... Ophthalmology. 2013 Nov;120(11):2324-31. doi: 10.1016/j.ophtha.2013.04.016. Epub 2013 Jun 12. Fujinami K, Sergouniotis PI, Davidson AE, Mackay DS, Tsunoda K, Tsubota K, Robson AG, Holder GE, Moore AT, Michaelides M, Webster AR
The clinical effect of homozygous ABCA4 alleles in 18 patients.
Ophthalmology. 2013 Nov;120(11):2324-31. doi: 10.1016/j.ophtha.2013.04.016. Epub 2013 Jun 12., [PMID:23769331]

Abstract [show]
PURPOSE: To describe the phenotypic presentation of a cohort of individuals with homozygous disease-associated ABCA4 variants. DESIGN: Retrospective case series. PARTICIPANTS: Eighteen affected individuals from 13 families ascertained from a total cohort of 214 families with ABCA4-related retinal disease presenting to a single center. METHODS: A detailed history was obtained, and color fundus photography, autofluorescence (AF) imaging, optical coherence tomography (OCT), and electrophysiologic assessment were performed. Phenotypes based on ophthalmoscopy, AF, and electrophysiology were assigned using previously reported characteristics. ABCA4 mutation detection was performed using the ABCR400 microarray (Asper Biotech, Tartu, Estonia) and high-throughput DNA sequencing, with direct sequencing used to assess segregation. MAIN OUTCOME MEASURES: Detailed clinical, electrophysiologic, and molecular genetic findings. RESULTS: Eleven disease-associated homozygous ABCA4 alleles were identified, including 1 frame shift, 2 stops, 1 intronic variant causing splice-site alteration, 2 complex missense variants, and 5 missense variants: p.Glu905fsX916, p.Arg1300X, p.Gln2220X, c.4253+4 C>T, p.Leu541Pro and p.Ala1038Val (homozygosity for complex allele), p.Val931Met and p.Arg1705Gln (complex allele), p.Arg212Cys, p.Cys1488Arg, p.Arg1640Trp, p.Gly1961Glu, and p.Leu2027Phe. Eight of these 11 homozygous alleles have not been reported previously. Six of 7 patients with homozygous null alleles had early-onset (<10 years) disease, with all 7 having a severe phenotype. Two patients with homozygous missense variants (p.Leu541Pro and p.Ala1038Val [complex], and p.Arg1640Trp) presented with a severe phenotype. Three patients with homozygous p.Gly1961Glu had adult-onset disease and a mild phenotype. One patient with homozygous p.Leu2027Phe showed a spared fovea and preserved visual acuity. CONCLUSIONS: The phenotypes represented in patients identified as homozygous for presumed disease-associated ABCA4 variants gives insight into the effect of individual alleles. Null alleles have severe functional effects, and certain missense variants are similar to nulls, suggesting complete abrogation of protein function. The common alleles identified, p.Gly1961Glu and p. Leu2027Phe, both have a mild structural and functional effect on the adult retina; the latter is associated with relatively retained photoreceptor architecture and function at the fovea.

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7 Results: Eleven disease-associated homozygous ABCA4 alleles were identified, including 1 frame shift, 2 stops, 1 intronic variant causing splice-site alteration, 2 complex missense variants, and 5 missense variants: p.Glu905fsX916, p.Arg1300X, p.Gln2220X, c.4253&#fe;4 C>T, p.Leu541Pro and p.Ala1038Val (homozygosity for complex allele), p.Val931Met and p.Arg1705Gln (complex allele), p.Arg212Cys, p.Cys1488Arg, p.Arg1640Trp, p.Gly1961Glu, and p.Leu2027Phe. Login to comment
10 Two patients with homozygous missense variants (p.Leu541Pro and p.Ala1038Val [complex], and p.Arg1640Trp) presented with a severe phenotype. Login to comment
60 Sex Ethnicity Consanguinity Age at Onset (yrs) Age (yrs) Duration of Disease (yrs) LogMAR VA Fundus Appearance AF Pattern ERG Group OCT Central Foveal Thickness (mm) Mutation Status RE LE RE LE 1 1 M S Asian Yes (1st cousin) 11 33 22 1.0 1.0 2 2 1 64 69 c.634 C>T, p.Arg212Cys 2 1 F S Asian Yes (1st cousin) 11 36 25 1.0 1.0 2 2 3 31 41 c.634 C>T, p.Arg212Cys 3* 2 M European No 3 8 5 1.2 1.2 2 2 3y 41 36 c.1622 T>C, p.Leu541Pro / c.3113 C>T, p.Ala1038Val 4 3 F S Asian Yes (2nd cousin once removed) 5 8 3 1.0 1.0 2 2 3 NA NA c.2713delG, p.Glu905fsX916 5 4 M S Asian Yes (unknown) 10 25 15 1.0 1.08 2 2 3 64 60 c.2791 G>A, p.Val931Met / c.5114 G>A, p.Arg1705Gln 6 5 M S Asian Yes (1st cousin) 10 30 20 1.0 1.0 2 2 3 NA NA c.4462 T>C, p.Cys1488Arg 7 5 F S Asian Yes (1st cousin) 10 22 12 2.0 1.0 2 2 3 NA NA c.4462 T>C, p.Cys1488Arg 8 6 M ME Asian Yes (1st cousin) 30 36 6 1.08 2.0 3 3 3 103 95 c.4918 C>T, p.Arg1640Trp 9 7 F S Asian Yes (2nd cousin) 19 27 8 1.78 2.0 1 2 1 128 90 c.5882 G>A, p.Gly1961Glu 10 7 M S Asian Yes (2nd cousin) 30 34 4 0.48 0.48 1 2 1 NA NA c.5882 G>A, p.Gly1961Glu 11 8 F S Asian Yes (1st cousin) 17 26 9 0.78 0.78 1 1 1 54 47 c.5882 G>A, p.Gly1961Glu 12 9 F European No 44 44 0 0.18 0.0 2 2 1 NA NA c.6079 C>T, p.Leu2027Phe 13 10 M ME Asian Yes (1st cousin) 5 11 6 1.3 1.0 3 2 3 62 68 c.3898 C>T, p.Arg1300X 14 11 M S Asian Yes (unknown) 8 11 3 1.0 1.0 2 2 3 NA NA c.4253&#fe;4 C>T 15 12 M S Asian Yes (1st cousin) 9 48 39 3.0 3.0 3 NA 3 NA NA c.6658 C>T, p.Gln2220X 16 13 M S Asian Yes (uncle and niece) 4 7 3 1.08 1.08 1 NA 3 NA NA c.6658 C>T, p.Gln2220X 17 13 M S Asian Yes (uncle and niece) 6 8 2 1.08 1.0 1 NA 3 NA NA c.6658 C>T, p.Gln2220X 18 13 M S Asian Yes (1st cousin) 17 25 8 1.78 1.78 3 NA 3 NA NA c.6658 C>T, p.Gln2220X AF &#bc; autofluorescence; ERG &#bc; electroretinography; F &#bc; female; FM No. Login to comment
100 Patient 3, homozygous for both p.Leu541Pro and p.Ala1038Val, showed a very severe phenotype: age of onset (3 years), visual acuity (1.2 for both eyes), type 2 fundus appearance, type 2 AF pattern, and ERG group 3. Login to comment
120 Patient 3, homozygous for p.Leu541Pro and p.Ala1038Val, had a very early onset associated with severe disease. Login to comment
125 In conclusion, 2 patients were homozygous for 2 variants previously reported as associated with disease (patient 3, p.Leu541Pro and p.Ala1038Val; patient 5, p.Val931Met and p.Arg1705Gln; Table 4, available at http://aaojournal.org). Login to comment
126 However, p.Ala1038Val and p.Val931Met were present in a relatively high number of chromosomes on the Exome Variant Server database and were predicted to be tolerant by Sorting Intolerant from Tolerance analysis. Login to comment

[hide] Characterization of stargardt disease using polari... Invest Ophthalmol Vis Sci. 2013 Sep 27;54(9):6416-25. doi: 10.1167/iovs.12-11550. Ritter M, Zotter S, Schmidt WM, Bittner RE, Deak GG, Pircher M, Sacu S, Hitzenberger CK, Schmidt-Erfurth UM
Characterization of stargardt disease using polarization-sensitive optical coherence tomography and fundus autofluorescence imaging.
Invest Ophthalmol Vis Sci. 2013 Sep 27;54(9):6416-25. doi: 10.1167/iovs.12-11550., [PMID:23882696]

Abstract [show]
PURPOSE: To identify disease-specific changes in Stargardt disease (STGD) based on imaging with polarization-sensitive spectral-domain optical coherence tomography (PS-OCT) and to compare structural changes with those visible on blue light fundus autofluorescence (FAF) imaging. METHODS: Twenty-eight eyes of 14 patients diagnosed with STGD were imaged using a novel high-speed, large-field PS-OCT system and FAF (excitation 488 nm, emission > 500 nm). The ophthalmoscopic phenotype was classified into three groups. ABCA4 mutation testing detected 15 STGD alleles, six of which harbor novel mutations. RESULTS: STGD phenotype 1 (12 eyes) showed sharply delineated areas of absent RPE signal on RPE segmentation B-scans of PS-OCT correlating with areas of hypofluorescence on FAF. Adjacent areas of irregular fluorescence correlated with an irregular RPE segmentation line with absence of overlaying photoreceptor layers. Eyes characterized on OCT by a gap in the subfoveal outer segment layer (foveal cavitation) showed a normal RPE segmentation line on PS-OCT. Hyperfluorescent flecks on FAF in phenotype 2 STGD (8 eyes) were identified as clusters of depolarizing material at the level of the RPE. Distribution of flecks could be depicted on RPE elevation maps. An increased amount of depolarizing material in the choroid was characteristic for STGD Phenotype 3 (8 eyes). CONCLUSIONS: PS-OCT together with FAF identified characteristic patterns of changes in different stages of the disease. PS-OCT is a promising new tool for diagnosis and evaluation of future treatment modalities in STGD.

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105 ߤ Linked to c.3113C>T (p.Ala1038Val). Login to comment
143 [1622T>C; 3113C>T] (p.[Leu541Pro; Ala1038Val]), which is generally considered to be associated with more severe disease progression.40 Patient 12 carried this allele together with the same novel missense mutation (p.Glu955Gly) on the second chromosome as his younger sister (patient 10, STGD phenotype 2), which is suggestive of intrafamilial phenotype variation associated with this specific combination of ABCA4 mutations. Login to comment
198 [1622T>C; 3113C>T p.[Leu541Pro; Ala1038Val]), respectively. Login to comment

[hide] Clinical and molecular analysis of Stargardt disea... Am J Ophthalmol. 2013 Sep;156(3):487-501.e1. doi: 10.1016/j.ajo.2013.05.003. Fujinami K, Sergouniotis PI, Davidson AE, Wright G, Chana RK, Tsunoda K, Tsubota K, Egan CA, Robson AG, Moore AT, Holder GE, Michaelides M, Webster AR
Clinical and molecular analysis of Stargardt disease with preserved foveal structure and function.
Am J Ophthalmol. 2013 Sep;156(3):487-501.e1. doi: 10.1016/j.ajo.2013.05.003., [PMID:23953153]

Abstract [show]
PURPOSE: To describe a cohort of patients with Stargardt disease who show a foveal-sparing phenotype. DESIGN: Retrospective case series. METHODS: The foveal-sparing phenotype was defined as foveal preservation on autofluorescence imaging, despite a retinopathy otherwise consistent with Stargardt disease. Forty such individuals were ascertained and a full ophthalmic examination was undertaken. Following mutation screening of ABCA4, the molecular findings were compared with those of patients with Stargardt disease but no foveal sparing. RESULTS: The median age of onset and age at examination of 40 patients with the foveal-sparing phenotype were 43.5 and 46.5 years. The median logMAR visual acuity was 0.18. Twenty-two patients (22/40, 55%) had patchy parafoveal atrophy and flecks; 8 (20%) had numerous flecks at the posterior pole without atrophy; 7 (17.5%) had mottled retinal pigment epithelial changes; 2 (5%) had multiple atrophic lesions, extending beyond the arcades; and 1 (2.5%) had a bull's-eye appearance. The median central foveal thickness assessed with spectral-domain optical coherence tomographic images was 183.0 mum (n = 33), with outer retinal tubulation observed in 15 (45%). Twenty-two of 33 subjects (67%) had electrophysiological evidence of macular dysfunction without generalized retinal dysfunction. Disease-causing variants were found in 31 patients (31/40, 78%). There was a higher prevalence of the variant p.Arg2030Gln in the cohort with foveal sparing compared to the group with foveal atrophy (6.45% vs 1.07%). CONCLUSIONS: The distinct clinical and molecular characteristics of patients with the foveal-sparing phenotype are described. The presence of 2 distinct phenotypes of Stargardt disease (foveal sparing and foveal atrophy) suggests that there may be more than 1 disease mechanism in ABCA4 retinopathy.

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45 Mutation screening of ABCA4 was performed with the arrayed primer extension (APEX) microarray (ABCR400 chip, Asper Ophthalmics, TABLE 1. Summary of Clinical Findings and Molecular Status of 40 Patients With a Foveal-Sparing Phenotypea of Stargardt Disease Patient Onsetb (y) Age (y) LogMAR Visual Acuity Fundus Patternc OCT ERGe Mutation Status CFTd (mm) ORT Group PERG mfERG OD OS OD OS OD OS OD OS 1 45 45 0 0 3 219 223 NA NA NA NA NA [c.1411 G>A, p.Glu471Lys/c.2588 G>C, p. Gly863Ala/c.4594 G>A, p.Asp1532Asn/c.5693 G>A, p.Arg1898His] 2 33 33 0.18 0.48 1 NA NA 3 ND ND NA NA [c.1622 T>C, p.Leu541Pro/c.3113 C>T, p.Ala1038Val/c.6089 G>A, p.Arg2030Gln] 3 53 66 0.18 0.18 1 NA NA 2 A A NA NA [c.768 G>T, Splice site/c. 6320 G>A, p. Arg2107His ] 4 37 54 1.48 0.18 1 32 39 U 3 ND ND 2 2 [c.1760 &#fe;1 G>T, Splice site/c.4594 G>T, p.Asg1532Tyr ] 5 57 57 0.3 0.18 1 NA NA 1 ND ND NA NA [c. Login to comment
47 6089 G>A, p.Arg2030Gln/c.6118 C>T, p.Arg2040*] 8 39 44 0.1 0.1 4 297 230 U 3 A A NA NA [c.71 G>A, p.Arg24His/c.4577 C>T, p. Thr1526Met] 9 35* 35 0.18 0.18 2 142 154 3 ND ND NA NA [c.658 C>T, p.p.Arg220Cys/c.2588 G>C, p. Gly863Ala] 10 45 54 0.48 0.18 1 102 116 3 ND A NA NA [c.1957 C>T, p.Arg653Cys/c.5693 G>A, p.Arg1898His] 11 43 43 0.1 0 2 170 185 1 A A 2 2 [c.2588 G>C, p. Gly863Ala/c.4139 C>T, p.Ala1038Val] 12 36** 38 0.3 0 1 220 212 U 1 A A 1 1 [c.4139 C>T, p.Ala1038Val/c.4594 G>T, p.Asp1532Asn] 13 62 68 0.1 0.48 1 196 189 U 1 N N 2 2 [c.4222 T>C, p.Trp1408Arg/c.4918 C>T, p.Arg1640Trp] 14 36 44 0.48 0.48 3 79 89 1 A A NA NA [c.4222 T>C, p.Trp1408Arg/c.4918 C>T, p.Arg1640Trp] 15 46* 46 0.1 0.1 3 NA NA 1 A A NA NA [c.4469 G>A, p.Cys1490Tyr/c. Login to comment
127 2588G>C, p.Gly863Ala 4 Het Allikmets46 Intol. 0.01 PRD 0.996 No change 68/13006 db SNP (rs76157638) 21 c.3113C>T, p.Ala1038Val 1 Het Webster53 Tol. NA Benign 0.014 Donor 43.5 70 New site (&#fe;61.72) 22/13006 db SNP (rs61751374) 24 c.3602T>G, p.Leu1201Arg 2 Het Lewis48 Tol. NA Benign 0.052 Donor 61.3 74 New site (&#fe;20.08) 416/13006 db SNP (rs61750126) 27 c.3898C>T, p.Arg1300* 1 Het Rivera49 NA NA ND 28 c.4139C>T, p.Pro1380Leu 2 Het Lewis48 Intol. 0.01 Benign 0.377 No change 2/13006 db SNP (rs61750130) 28 c.4222 T>C, p.Trp1408Arg 2 Het Lewis48 Tol. NA PRD 0.845 No change ND dbSNP (rs61750135) 29 c.4319T>C, p.Phe1440Ser 1 Het Lewis48 Tol. NA PRD 0.744 No change ND dbSNP (rs61750141) 30 c.4469G>A, p.Cys1490Tyr 1 Het Webster53 Intol. 0.03 PRD 0.994 No change ND dbSNP (rs61751402) 31 c.4577C>T, p.Thr1526Met 1 Het Lewis48 Intol. 0.00 PRD 0.91 No change ND db SNP (rs61750152) 31 c.4594G>T, p.Asp1532Asn 3 Het Lewis48 Tol. NA PRD 0.853 No change ND 33 c.4685T>C, p.Ile1562Thr 1 Het Allikmets46 Tol. NA Benign 0.034 No change 18/13006 db SNP (rs1762111) 35 c.4956T>G, p.Tyr1652* 1 Het Fumagalli52 NA NA Acceptor 43 72 New site (&#fe;67.36) ND 35 c.4918C>T, p.Arg1640Trp 2 Het Rozet47 Intol. 0.00 PRD 1 No change ND dbSNP (rs61751404) 35 c.4926C>G, p.Ser1642Arg 1 Het Birch50 Tol. 0.68 Benign 0.116 No change ND db SNP (rs61753017) Int 35 c.5018&#fe;2T>C, Splice site 1 Het Fumagalli52 NA NA Donor 81.2 54 WT site broken (33.07) ND Int 38 c.5461-10T>C 3 Het Briggs50 NA NA No change 3/13006 db SNP (rs1800728) 40 c.5693G>A, p.Arg1898His 2 Het Allikmets46 NA Benign 0.00 No change 25/13006 db SNP (rs1800552) 42 c.5882G>A, p.Gly1961Glu 1 Het Allikmets46 Tol. 0.18 PRD 1 No change 41/13006 db SNP (rs1800553) 44 c.6079C>T, p.Leu2027Phe 4 Homo Lewis48 Intol. 0.02 PRD 0.999 No change 4/13006 db SNP (rs61751408) 44 c.6089G>A, p.Arg2030Gln 4 Het Lewis48 Tol. NA PRD 0.995 No change 8/13006 db SNP (rs61750641) 44 c.6118C>T, p.Arg2040* 1 Het Rosenberg54 NA NA ND 46 c.6320G>A, p.Arg2107His 1 Het Fishman8 Intol. 0.00 PRD 0.996 No change 91/13006 db SNP (rs62642564) EVS &#bc; Exome Variant Server; HSF &#bc; Human Splicing Finder program; Hum var score &#bc; Human var score; Int &#bc; intron; Intol &#bc; intolerant; Mt CV &#bc; mutant consensus value; NA &#bc; not applicable; ND &#bc; not detected; PRD &#bc; probably damaging; Pred. &#bc; prediction; SIFT &#bc; Sorting Intolerant from Tolerance program; Tol. &#bc; tolerant; Wt CV &#bc; wild-type consensus value. Login to comment
141 Allele Frequencies of 72 ABCA4 Variants Identified in a Comparison Groupa With the Typical Stargardt Disease (140 Patients Without Evidence of Foveal Sparing on Autofluorescence Imaging) Exon Nucleotide Substitution and Amino Acid Change Number of Alleles Allele Frequency 2 c.71G>A, p.Arg24His 1 0.36% 2 c.161G>A, p.Cys54Tyr 3 1.07% 3 c.223T>G, p.Cys75Gly 1 0.36% 5 c.455G>A, p.Arg152Gln 1 0.36% 5 c.454C>T, p.Arg152* 1 0.36% 5 c.466 A>G, p.Ile156Val 2 0.71% 6 c.634C>T, p. Arg212Cys 3 1.07% 6 c.656G>C, p.Arg219Thr 1 0.36% 6 c.666_678delAAAGACGGTGCGC, p.Lys223_Arg226delfs 2 0.71% 6 c.768G>T, Splicing site 4 1.42% 8 c.1037A>C, p.Lys346Thr 1 0.36% 10 c.1222C>T, p.Arg408* 3 1.07% 12 c.1622T>C, p.Leu541Pro 2 0.71% 12 c.1648 G>T, p.Gly550* 1 0.36% 13 c.1804C>T, p.Arg602Trp 1 0.36% 13 c.1817G>A, p.Gly606Asp 1 0.36% 13 c.1922G>C, p.Cys641Ser 1 0.36% Int 13 c.1937&#fe;1G>A, Splicing site 2 0.71% 14 c.1957C>T, p.Arg653Cys 2 0.71% 17 c.2588G>C, p.Gly863Ala 19 6.79% 18 c.2701A>G, p.Thr901Ala 1 0.36% 19 c.2791G>A, p.Val931Met 2 0.71% 19 c.2894A>G, p.Asn965Ser 1 0.36% 20 c.2966T>C, p.Vla989Ala 3 1.07% 20 c.2971G>C, p.Gly991Arg 2 0.71% 21 c.3056C>T, p.Thr1019Met 1 0.36% 21 c.3113C>T, p.Ala1038Val 3 1.07% 21 c.3064G>A, p.Glu1022Lys 2 0.71% 22 c.3211_3212insGT, p.Ser1071Cysfs 6 2.14% 22 c.3259G>A, p.Glu1087Lys 4 1.43% 22 c.3292C>T, p.Arg1098Cys 1 0.36% 22 c.3322C>T, p.Arg1108Cys 5 1.79% 22 c.3323G>A, p.Arg1108His 1 0.36% 23 c.3364G>A, p.Glu1122Lys 1 0.36% 23 c.3386G>A, p.Arg1129His 1 0.36% 24 c.3602T>G, p.Leu1201Arg 3 1.07% 27 c.3898C>T, p.Arg1300* 2 0.71% 28 c.4139C>T, p.Pro1380Leu 14 5.00% 28 c.4222T>C, p.Trp1408Arg 1 0.36% 28 c.4234C>T, p.Gly1412* 1 0.36% 28 c.4253&#fe;5G>T, Splice site 1 0.36% 28 c.4253&#fe;4C>T, Splice site 1 0.36% 29 c.4283C>T, p.Thr1428Met 1 0.36% 29 c.4319T>C, p.Phe1440Ser 1 0.36% 29 c.4462T>C, p.Cys1488Arg 1 0.36% 30 c.4469G>A, p.Cys1490Tyr 5 1.79% 30 c.4537_4538insC, p.Gly1513Profs 1 0.36% 31 c.4577C>T, p.Thr1526Met 2 0.71% 33 c.4715C>T, p.Thr1572Met 1 0.36% Continued on next page TABLE 3. Login to comment

[hide] Identification of three ABCA4 sequence variations ... Am J Ophthalmol. 2013 Dec;156(6):1220-1227.e2. doi: 10.1016/j.ajo.2013.07.008. Epub 2013 Sep 4. Utz VM, Chappelow AV, Marino MJ, Beight CD, Sturgill-Short GM, Pauer GJ, Crowe S, Hagstrom SA, Traboulsi EI
Identification of three ABCA4 sequence variations exclusive to African American patients in a cohort of patients with Stargardt disease.
Am J Ophthalmol. 2013 Dec;156(6):1220-1227.e2. doi: 10.1016/j.ajo.2013.07.008. Epub 2013 Sep 4., [PMID:24011517]

Abstract [show]
PURPOSE: To describe the clinical and molecular findings in ten unrelated African American patients with Stargardt disease. DESIGN: Retrospective, observational case series. METHODS: We reviewed the clinical histories, examinations, and genotypes of 85 patients with molecular diagnoses of Stargardt disease. Three ABCA4 sequence variations identified exclusively in African Americans were evaluated in 300 African American controls and by in silico analysis. RESULTS: ABCA4 sequence changes were identified in 85 patients from 80 families, of which 11 patients identified themselves as African American. Of these 11 patients, 10 unrelated patients shared 1 of 3 ABCA4 sequence variations: c.3602T>G (p.L1201R); c.3899G>A (p.R1300Q); or c.6320G>A (p.R2107H). The minor allele frequencies in the African American control population for each variation were 7.5%, 6.3%, and 2%, respectively. This is comparable to the allele frequency in African Americans in the Exome Variant Server. In contrast, the allele frequency of all three of these variations was less than or equal to 0.05% in European Americans. Although both c.3602T>G and c.3899G>A have been reported as likely disease-causing variations, one of our control patients was homozygous for each variant, suggesting that these are nonpathogenic. In contrast, the absence of c.6320G>A in the control population in the homozygous state, combined with the results of bioinformatics analysis, support its pathogenicity. CONCLUSIONS: Three ABCA4 sequence variations were identified exclusively in 10 unrelated African American patients: p.L1201R and p.R1300Q likely represent nonpathogenic sequence variants, whereas the p.R2107H substitution appears to be pathogenic. Characterization of population-specific disease alleles may have important implications for the development of genetic screening algorithms.

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70 However, patient 5 possessed two additional sequence variations: c.618C>T (p.S206S), a synonymous sequence variation that has been found to cosegregate with disease in a family with Stargardt disease,41 and c.2546T>C (p.V849A).25 Patient 6 exhibited both a c.3113C>T mutation (p.A1038V), present in 15% of our cohort, and a c.1937&#fe;1G>C sequence variation that results in a splice site mutation in intron 13.27 The c.3113C>T mutation produces a biochemically altered protein product42 and has been detected in patients with Stargardt disease but not in control patients.18,20,25 The third sequence variation, c.6320 G>A (p.R2107H), existed as a heterozygous sequence variation in patients 7, 8, 9, and 10. Login to comment
88 3113C>T (p.A1038V) 15 c.1937&#fe;1G>C (N/A) 0 7 c.6320G>A (p.R2107H) 0 c.IVS38-10T>C (N/A) 10 8 c.6320G>A (p.R2107H) 0 c.174C>G (p.N58K) 0 9 c.6320G>A (p.R2107H) 0 c.6286G>A (p.E2096K) 0 10 c.6320G>A (p.R2107H) 0 cDNA &#bc; complementary DNA; N/A &#bc; not applicable; % Popn &#bc; percentage of patients in the remaining population with the specific sequence variation; Pt &#bc; patient. Login to comment
121 Population-Specific ABCA4 Alleles in Patients with Stargardt Disease References Population Allele Protein Rivera et al.28 Hargitai et al.12 Hungaro-German c.1622T>C/c.3113C>T p.L541P/p.A1038V September et al.47 Afrikaner c.4469G>A p.C1490Y September et al.47 Afrikaner c.1804C>T p.R602W Rosenberg et al.48 Danish c.2894A>G p.N965S Maugeri et al.27 Western European c.2588G>C p.G863A Maia-Lopes et al.49 Portuguese c.32T>C p.L11P Valverde et al.29 Spanish c.5882G>A p.R1129L Fumagalli et al.50 Italian c.2099G>A p.W700X VOL. 156, NO. 6 ALL AUTHORS HAVE COMPLETED AND SUBMITTED THE ICMJE FORM FOR DISCLOSURE OF POTENTIAL CONFLICTS OF INTEREST, and the following were reported. Login to comment

[hide] Association between genotype and phenotype in fami... Mol Vis. 2014 Jan 7;20:89-104. eCollection 2014. Kjellstrom U
Association between genotype and phenotype in families with mutations in the ABCA4 gene.
Mol Vis. 2014 Jan 7;20:89-104. eCollection 2014., [PMID:24453473]

Abstract [show]
PURPOSE: To investigate the genotype and phenotype in families with adenosine triphosphate-binding cassette, sub-family A, member 4 (ABCA4)-associated retinal degeneration. METHODS: Three families with at least one family member with known homozygous or compound heterozygote mutations in the ABCA4 gene were studied. The investigations included full field electroretinography (ff-ERG), multifocal ERG (mERG), Goldmann visual fields, optical coherence tomography (OCT), and standard ophthalmological examination. Microarray (Asper) was used for ABCA4 genotyping. RESULTS: In family 1, the proband (age 23) was homozygote for the c768 G>T mutation. She was diagnosed with cone rod dystrophy (CRD) while her aunt (age 69) was compound heterozygote for the c768 G>T and c2894 A>G mutations and had autosomal recessive retinitis pigmentosa (arRP). The father (age 61) and the mother (age 60) of the proband were asymptomatic carriers of the c768 G>T mutation. In family 2, the proband (age 25) was homozygote for the c5917del. She was diagnosed with CRD. Her father and two sisters were compound heterozygote for the c5917del and c5882 G>A mutations. The eldest sister (age 23) suffered from Stargardt disease (STGD) while the youngest sister (age 12) and their father (age 48) had no visual complaints. Anyhow, their ERG measurements indicated changes corresponding to STGD. The mother (age 42), (heterozygote for the c5917 delG mutation) and the youngest child (age 9; heterozygote for the c5882 G>A mutation) had a normal phenotype. In family 3, the proband (age 43) was compound heterozygote for c768 G>T and c3113 C>T and had been diagnosed with STGD. Her son (age 12), who was homozygote for the c768 G>T mutation, had wider scotomas with earlier onset (age 6), ff-ERG cone responses in the lower range of normality, and reduced mERG. At the moment, he is classified as having STGD but may progress to CRD. The father (age 45) was asymptomatic and heterozygote for the c768 G>T mutation. The patients with progressive disorders (CRD or arRP) had prolonged implicit times for the 30 Hz flicker ff-ERG and the mERG. All patients with two mutations in the ABCA4 gene demonstrated attenuation of retinal thickness on the OCT macular map. CONCLUSIONS: This study confirms that ABCA4 mutations lead to a spectrum of retinal degenerations ranging from STGD to CRD or arRP. At the time of diagnosis, it is not possible to predict the severity of the condition only from genotyping. Our results suggest that prolongation of implicit times for the ff-ERG and/or mERG seem to be associated with progressive conditions such as CRD and arRP. Since ABCA4 mutations are common in the general population, different family members can harbor various combinations of mutations resulting in diverse phenotype and prognosis in the same family, further emphasizing the importance of a combination of genetic and electrophysiological tests at the first visit and follow-up.

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96 Subject ABCA4 allele 1 ABCA4 allele 2 Phenotype* Nucleotide change Effect Nucleotide change Effect 1 Ia c768 G>T V256V/splice c2894 A>G N965S/missense arRP 1 Ib c768 G>T V256V/splice ৄ ৄ NVP 1 Ic c768 G>T V256V/splice ৄ ৄ NVP 1 IIa c768 G>T V256V/splice c768 G>T V256V/splice CRD 2 Ia c5917 delG V1973X/frameshift ৄ ৄ NVP 2 Ib c5917 delG V1973X/frameshift c5882 G>A G1961E/missense STGD 2 IIa c5917 delG V1973X/frameshift c5917 delG V1973X/frameshift CRD 2 IIb c5917 delG V1973X/frameshift c5882 G>A G1961E/missense STGD 2 IIc c5917 delG V1973X/frameshift c5882 G>A G1961E/missense STGD 2 II d c5882 G>A G1961E/missense ৄ ৄ NVP 3 Ia c768 G>T V256V/splice c3113 C>T A1038V/missense STGD 3 Ib c768 G>T V256V/splice ৄ ৄ NVP 3 IIa c768 G>T V256V/splice c768 G>T V256V/splice STGD Abbreviations: arRP; autosomal recessive retinitis pigmentosa, CRD; cone rod dystrophy, STGD; Stargardt disease, NVP; no visual problems *clinical presentation at last visit T able 3. Login to comment

[hide] Inner and outer retinal changes in retinal degener... Invest Ophthalmol Vis Sci. 2014 Mar 20;55(3):1810-22. doi: 10.1167/iovs.13-13768. Huang WC, Cideciyan AV, Roman AJ, Sumaroka A, Sheplock R, Schwartz SB, Stone EM, Jacobson SG
Inner and outer retinal changes in retinal degenerations associated with ABCA4 mutations.
Invest Ophthalmol Vis Sci. 2014 Mar 20;55(3):1810-22. doi: 10.1167/iovs.13-13768., [PMID:24550365]

Abstract [show]
PURPOSE: To investigate in vivo inner and outer retinal microstructure and effects of structural abnormalities on visual function in patients with retinal degeneration caused by ABCA4 mutations (ABCA4-RD). METHODS: Patients with ABCA4-RD (n = 45; age range, 9-71 years) were studied by spectral-domain optical coherence tomography (OCT) scans extending from the fovea to 30 degrees eccentricity along horizontal and vertical meridians. Thicknesses of outer and inner retinal laminae were analyzed. Serial OCT measurements available over a mean period of 4 years (range, 2-8 years) allowed examination of the progression of outer and inner retinal changes. A subset of patients had dark-adapted chromatic static threshold perimetry. RESULTS: There was a spectrum of photoreceptor layer thickness changes from localized central retinal abnormalities to extensive thinning across central and near midperipheral retina. The inner retina also showed changes. There was thickening of the inner nuclear layer (INL) that was mainly associated with regions of photoreceptor loss. Serial data documented only limited change in some patients while others showed an increase in outer nuclear layer (ONL) thinning accompanied by increased INL thickening in some regions imaged. Visual function in regions both with and without INL thickening was describable with a previously defined model based on photoreceptor quantum catch. CONCLUSIONS: Inner retinal laminar abnormalities, as in other human photoreceptor diseases, can be a feature of ABCA4-RD. These changes are likely due to the retinal remodeling that accompanies photoreceptor loss. Rod photoreceptor-mediated visual loss in retinal regionswith inner laminopathy at the stages studied did not exceed the prediction from photoreceptor loss alone.

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74 Characteristics of the ABCA4-Related Retinal Disease Patients Patient Age at Visits, y Sex Allele 1 Allele 2 Previous Report*ߤ P1 9, 12 M E341G F608I P2 9, 15 M R681X C2150Y P28* P3ߥ 12 M N965S W821R P1ߤ P4 13, 16 M V256V T1526M P21*, P15ߤ P5 14, 20 F W1408R IVS40&#fe;5 G>A P49* P6ߥ 16 F V989A IVS28&#fe;5 G>T P17ߤ P7ߥ 16 M N965S W821R P18ߤ P8 18, 20 F Y362X IVS38-10 T>C P9ߥ 18 F V989A IVS28&#fe;5 G>T P10 18, 22 M G1961E R1129L P3ߤ P11 20 M R1640Q c.5174_5175insG P12ߥ 20 M G1961E G1961E/P68L P13 22, 25 M G863A IVS35&#fe;2 T>C P20ߤ P14 22, 24 F G1961E R152X P12*, P21ߤ P15ߥ 23 M G1961E G1961E/P68L P16 25, 27 M G1961E R152X P11* P17 26, 32 F L1940P R1129L P64* P18 27, 34 F R1925G A1038V/L541P P19 27, 29 M c.4530_4531insC R1705Q P52*, P5ߤ P20 28, 30 F G1961E A1038V/L541P P23ߤ P21 31, 35 M T1019M G1961E P34* P22ߥ 32, 37 M P1486L Deletion of exon 7 P25ߤ P23 33, 35 M G863A R1108C P29*, P6ߤ P24 34, 37 F IVS40&#fe;5 G>A V935A P32*, P7ߤ P25 34 M G1961E &#a7; P8ߤ P26 37, 43 F C54Y G863A P4* P27 39, 44 F G863A C1490Y P30*, P26ߤ P28 40 M G1961E C54Y P7*, P10ߤ P29 41 F IVS38-10 T>C E1087D P59* P30ߥ 43, 47 F G1961E V256V P23*, P11ߤ P31ߥ 47, 51 F P1486L Deletion of exon 7 P32 47 M Y245X Y245X P20* P33ߥ 48, 51 F G1961E V256V P22*, P12ߤ P34 48, 50 F c.3208_3209insTG IVS40&#fe;5 G>A P35 50, 54 M V1433I L2027F P50* P36ߥ 52, 55 F T1526M R2030Q P55*, P28ߤ P37 53, 59 F G1961E P1380L P47*, P13ߤ P38ߥ 53, 61 M L1940P IVS40&#fe;5 G>A P61* P39 58 M D600E R18W P2*, P14ߤ P40 59, 62 M E1122K G1961E P44* P41 59, 62 F R1640Q G1961E P58* P42ߥ 62 F T1526M R2030Q P54* P43ߥ 64, 68 M L1940P IVS40&#fe;5 G>A P62* P44 68 F R1108C IVS40&#fe;5 G>A P42* P45 71 F IVS38-10 T>C &#a7; Novel variants are bold and italicized. Login to comment

[hide] Quantitative fundus autofluorescence in recessive ... Invest Ophthalmol Vis Sci. 2014 May 1;55(5):2841-52. doi: 10.1167/iovs.13-13624. Burke TR, Duncker T, Woods RL, Greenberg JP, Zernant J, Tsang SH, Smith RT, Allikmets R, Sparrow JR, Delori FC
Quantitative fundus autofluorescence in recessive Stargardt disease.
Invest Ophthalmol Vis Sci. 2014 May 1;55(5):2841-52. doi: 10.1167/iovs.13-13624., [PMID:24677105]

Abstract [show]
PURPOSE: To quantify fundus autofluorescence (qAF) in patients with recessive Stargardt disease (STGD1). METHODS: A total of 42 STGD1 patients (ages: 7-52 years) with at least one confirmed disease-associated ABCA4 mutation were studied. Fundus AF images (488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density to yield qAF. Texture factor (TF) was calculated to characterize inhomogeneities in the AF image and patients were assigned to the phenotypes of Fishman I through III. RESULTS: Quantified fundus autofluorescence in 36 of 42 patients and TF in 27 of 42 patients were above normal limits for age. Young patients exhibited the relatively highest qAF, with levels up to 8-fold higher than healthy eyes. Quantified fundus autofluorescence and TF were higher in Fishman II and III than Fishman I, who had higher qAF and TF than healthy eyes. Patients carrying the G1916E mutation had lower qAF and TF than most other patients, even in the presence of a second allele associated with severe disease. CONCLUSIONS: Quantified fundus autofluorescence is an indirect approach to measuring RPE lipofuscin in vivo. We report that ABCA4 mutations cause significantly elevated qAF, consistent with previous reports indicating that increased RPE lipofuscin is a hallmark of STGD1. Even when qualitative differences in fundus AF images are not evident, qAF can elucidate phenotypic variation. Quantified fundus autofluorescence will serve to establish genotype-phenotype correlations and as an outcome measure in clinical trials.

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47 In some cases where no mutations were detected by the array, or in more recently recruited patients, the next generation sequencing of the entire ABCA4 open reading frame and adjacent intronic sequences was performed on the Roche 454 platform.30 The four most common mutations found in six or more patients were: G1961E (12 patients from 11 families); L541P/ A1038V (eight patients from five families); L2027F (six patients from five families); and P1380L (six patients from six families). Login to comment
49 For the purposes of analyses reported below, we will refer to those eight mutations as the ''more common mutations.`` In two patients (two families), A1038V was present in a compound heterozygous state with other mutations while not as a complex allele with L541P (Table 1). Login to comment
77 [L541P; A1038V] 639 627 1.9 2.0 1.2 M 7 1 0.30 0.18 - I p. Login to comment
78 [L541P; A1038V] 413 1.9 2 F 25 11 0.80 0.80 II II p.G863A; c.5898&#fe;1G > A 710 675 3.4 3.3 3 M 11 6 0.80 0.70 I - p.G1961E; p.P1380L 267 2.3 4.1 M 35 10 0.30 0.18 I - p.G1961E; p. Login to comment
79 [L541P; A1038V] 426 2.1 4.2 M 35 10 0.40 0.48 I I p.G1961E; p. Login to comment
80 [L541P; A1038V] 356 354 1.7 1.8 5 F 14 1 0.60 0.60 II II p.L2027F; p.T972N 737 718 2.3 2.6 6 M 45 31 1.00 0.88 I I p.G1961E; p.P1380L 623 543 4.2 4.0 7 F 42 5 0.30 CF - I p.E1252* 557 2.1 8 M 15 4 0.80 0.80 II II p.L2027F; p.R2077W 728 697 3.2 3.2 9 F 24 2 0.60 0.40 II II p.R1161S 571 647 3.8 3.5 10 M 46 15 1.30 1.30 I I p.G1961E; p.Q636H 394 351 2.3 2.4 11.1 M 12 2 1.00 1.00 II - p. Login to comment
81 [L541P; A1038V]; p.R1640W 911 3.3 11.2 F 10 4 1.00 1.00 II - p. Login to comment
82 [L541P; A1038V]; p.R1640W 850 4.4 12 F 27 9 1.30 1.00 - III p.P1380L; p.P1380L 577 4.8 13 F 39 8 0.12 0.00 - I c.250_251insCAAA 616 2.3 14 M 23 4 0.88 0.60 - II p.C54Y 535 5.1 15.1 M 49 17 1.00 0.88 I I p.Y1557C 646 604 4.1 3.9 15.2 M 46 7 0.10 0.48 I I p.Y1557C 456 508 2.6 2.3 16.1 F 27 14 0.88 0.88 III III p.L2027F; p.G851D 448 459 6.0 6.3 16.2 F 29 19 1.30 1.18 III III p.L2027F; p.G851D 538 569 7.4 7.9 17 M 22 18 1.30 1.00 III III p.P1380L; p.R2030Q 434 411 5.7 6.0 18 M 37 16 0.70 0.70 I I p.G1961E; p.G1961E 281 279 2.6 2.2 19 F 33 5 0.88 0.70 I I p.G1961E; c.4540-2A > G 412 420 2.5 2.8 20 F 26 12 0.60 0.60 - I p.G1961E; p. Login to comment
83 [L541P; A1038V] 398 2.4 21 F 45 31 0.88 0.88 I I p.R1640W 647 613 2.6 2.8 22 M 43 7 1.00 0.00 - III p.A1773V; p.G1591G 640 6.9 23 F 41 1 0.10 CF II II p.P1486L; p.A1598D 613 572 6.0 6.5 24 F 19 4 0.60 0.70 I - p.G1961E; p.P1380L 368 2.4 25 F 23 4 0.88 0.80 - I p. Login to comment
84 [A854T; A1038V]; p.C2150Y 512 2.3 26 F 52 1 0.70 0.48 I - p.R212C 722 2.0 27 F 52 13 1.00 1.00 - I p.A1038V; p.A848D 459 4.1 28 M 20 5 0.30 0.40 I - p.L2027F; p.R1108H 507 2.3 29 M 23 7 1.00 1.00 I I p.G1961E; p.R2030Q 334 347 2.4 2.0 30 M 44 26 0.70 0.70 - II p.P1380L; p.R1108H 453 4.7 31 F 30 22 1.00 1.30 - I p.G1961E; c.6005&#fe;1G > T 428 2.3 32 M 12 8 0.40 0.40 I - p.W821R; p.C2150Y 306 2.0 33 F 20 9 0.88 0.88 III III p.R602W; p.M1882I 650 655 2.6 2.5 34 F 47 4 0.40 0.40 I - p.G1961E; p.R1129C 400 2.5 35 F 19 3 0.70 0.48 II II p. Login to comment
85 [L541P; A1038V]; p.L2027F 733 749 3.9 4.0 36 F 20 7 0.88 1.00 II II p.R1640W 571 552 3.4 3.8 37 F 12 3 0.80 0.80 I I p.R1108C; p.Q1412* 536 501 1.7 1.7 * All subjects were white, except for patients 10, 22, and 36 who were Indian, Hispanic, and black, respectively. Login to comment
135 Comparing each of the four most common mutations separately with healthy eyes, G1961E (P &#bc; 0.001); L541P/ A1038V (P < 0.001); L2027F (P < 0.001); and P1380L (P &#bc; 0.024) eyes had qAF8 that was significantly higher than in FIGURE 2. Login to comment
146 When corrected for age (P &#bc; 0.04) and sex (P &#bc; 0.004), compared with all other patients who did not have that particular mutation, the mutations L2027F (P &#bc; 0.009) and L541P/A1038V (P &#bc; 0.015) were associated with higher qAF8, while A1038V (when not in conjunction with L541P, P &#bc; 0.06); G851D (P &#bc; 0.006); and G1961E (P < 0.001) were associated with lower qAF8 in this sample. Login to comment
152 Genotype-Phenotype Relations (TF) When compared separately with healthy eyes, three of the four most common mutations, L541P/A1038V (P < 0.001); L2027F (P < 0.001); and P1380L (P &#bc; 0.001), had TF that was significantly higher than in healthy eyes, when corrected for age. Login to comment
180 The mutations were confirmed in six or more patients (G1961E, L541P/A1038V, L2027F, and P1380L) or in two to four patients (R1640W, Y1557C, G851D, and R2030Q). Login to comment
181 Also shown is mutation A1038V in a compound heterozygous state with other mutations while not as a complex allele with L541P. Login to comment
226 For example, based on our cross-sectional data, the mutations L2027F and L541P/A1038V seem to confer a faster rate of accumulation, whereas G1961E and G851D seems to confer a slower increase (Fig. 5). Login to comment
227 The complex allele L541P/A1038V involves missense mutations in both the exocytoplasmic domain-1 and nucleotide FIGURE 7. Login to comment
230 binding domain (NBD)-1 and confers severe STGD1 with relatively early onset of retina-wide disease.44-47 In our study, the L541P/A1038V complex allele was in some patients associated with high qAF8 even at young ages, while in other patients, particularly in those compound heterozygous for L541P/A1038V and G1961E, qAF8 values were relatively lower (Fig. 5). Login to comment
232 Thus it is likely that in these cases, the lower qAF values do not reflect a decrease in qAF after an earlier rapid elevation, but rather a slower increase in qAF8 due to the presence of the G1961E allele (L541P/A1038V &#fe; G1961E). Login to comment

[hide] Generalized choriocapillaris dystrophy, a distinct... Invest Ophthalmol Vis Sci. 2014 Apr 29;55(4):2766-76. doi: 10.1167/iovs.13-13391. Bertelsen M, Zernant J, Larsen M, Duno M, Allikmets R, Rosenberg T
Generalized choriocapillaris dystrophy, a distinct phenotype in the spectrum of ABCA4-associated retinopathies.
Invest Ophthalmol Vis Sci. 2014 Apr 29;55(4):2766-76. doi: 10.1167/iovs.13-13391., [PMID:24713488]

Abstract [show]
PURPOSE: We describe a particular form of autosomal recessive generalized choriocapillaris dystrophy phenotype associated with ABCA4 mutations. METHODS: A cohort of 30 patients with identified ABCA4 mutations and a distinct phenotype was studied. A retrospective review of history, fundus photographs, electroretinography, visual field testing, dark adaptometry, and optical coherence tomography was performed. Genetic analyses were performed by ABCA4 microarray analysis, high resolution melting, and/or next generation sequencing of all protein-coding sequences of the ABCA4 gene. RESULTS: The earliest recorded manifestation of ABCA4-associated disease was a central bull's eye type of macular dystrophy that progressed to chorioretinal atrophy of the macula with coarse rounded hyperpigmentations and expanding involvement of the periphery. The mean age at first presentation was 10.3 years, the longest follow-up was 61 years. All patients had two ABCA4 mutations identified, confirming the molecular genetic diagnosis of an ABCA4-associated disease. Most patients harbored at least one mutation classified as "severe," the most common of which was the p.N965S variant that had been found previously at a high frequency among patients with ABCA4-associated retinal dystrophies in Denmark. CONCLUSIONS: Generalized choriocapillaris dystrophy is a progressive ABCA4-associated phenotype characterized by early-onset macular dystrophy that disperses and expands to widespread end-stage chorioretinal atrophy with profound visual loss. All cases in this study were confirmed as harboring two ABCA4 mutations. Most of the ABCA4 mutations were classified as "severe" explaining the early onset, panretinal degeneration, and fast progression of the disease.

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89 mutation (21%), p.G863A, c.2408delG, and p.L541P/A1038V. Login to comment
123 Summary of Detected Potential Pathogenic Variants (Known and Novel [in Bold Face]) Found in the ABCA4 Gene of Patients With Generalized Choriocapillaris Dystrophy Patient Method Mutation 1 Mutation 2 Nucleotide Protein Nucleotide Protein D513 NGS c.203C>T p.P68L c.2894A>G p.N965S D514 Microarray, NGS c.2894A>G p.N965S c.5461-10T>C - D516 NGS c.4926C>G p.S1642R c.5041_5055del p.V1681_C1685del D517 NGS c.5169C>G p.Y1723* c.6079C>T p.L2027F D137 Microarray, NGS c.2894A>G p.N965S c.2894A>G p.N965S D801 Microarray, NGS c.6386&#fe;1G>A Aberrant splicing c.4234C>T p.Q1412* D109 Microarray c.2894A>G p.N965S c.4234C>T p.Q1412* D040 Microarray c.6229C>T p.R2077W c.6229C>T p.R2077W D159 Microarray c.3113C>T p.L541P/A1038V c.3113C>T p.L541P/A1038V D129 Microarray c.2894A>G p.N965S c.3322C>T p.R1108C D115 Microarray c.2894A>G p.N965S c.3113C>T p.L541P/A1038V D033 Microarray c.2894A>G p.N965S c.2041C>T p.R681* D023 Microarray c.203C>T p.P68L c.3329-2A>G Aberrant splicing D001 Microarray c.666_678del p.K223_R226delfs c.4667&#fe;2T>C Aberrant splicing D147 Microarray, HRM c.2894A>G p.N965S c.2408delG p.G803fs D162 Microarray c.3329-2A>G Aberrant splicing c.6089G>A p.R2030Q D022 Microarray, HRM c.4462T>C p.C1488R c.4102C>T p.R1368C D112 Microarray, HRM c.2894A>G p.N965S c.1529T>G p.L510R D108 Microarray, HRM c.1648G>A p.G550R c.4102C>T p.R1368C D107 Microarray c.666_678del p.K223_R226delfs c.2588G>C p.G863A D070 Microarray c.2588G>C p.G863A c.2588G>C p.G863A D116 Microarray c.2300T>A p.V767D c.5461-10T>C - D135 Microarray, HRM c.2894A>G p.N965S c.2408delG p.G803fs D117 Microarray, HRM c.3191-2A>G Aberrant splicing c.2408delG p.G803fs D186 Microarray, HRM c.3322C>T p.R1108C c.6386&#fe;1G>A Aberrant splicing D173 Microarray, HRM c.4469G>A p.C1490Y c.2915C>A p.T972N TABLE 3. Login to comment
124 In Silico Analysis of ABCA4 Variants Detected in This Study Using Alamut 2.2 Software cDNA Variant Protein Variant Effect on Protein Function AGVGD Class SIFT Prediction Effect on Protein PPH2 Prediction Effect on Protein TASTER Prediction Effect on Splicing Missense variants c.203C>T p.P68L C65 Deleterious Probably damaging Disease causing c.1529T>G p.L510R C65 Deleterious Benign Polymorphism c.1622T>C p.L541P Reduced ATP binding mislocali- zation26,27 C65 Deleterious Probably damaging Disease causing c.1648G>A p.G550R C65 Deleterious Possibly damaging Disease causing New acceptor site c.2300T>A p.V767D Reduced protein28 C65 Deleterious Benign Disease causing c.2588G>C p.G863A Reduced protein level, reduced ATP binding, reduced ATPase activity26 C55 Deleterious Possibly damaging Disease causing Predicted change at acceptor site 1 bp upstream: 11.1%, creating a new stronger acceptor 3 bp downstream c.2894A>G p.N965S Reduced ATP binding26 C45 Deleterious Probably damaging Disease causing New acceptor site c.2915C>A p.T972N C55 Deleterious Probably damaging Disease causing c.3113C>T p.A1038V Reduced ATP binding, reduced ATP hydrolysis26 C65 Deleterious Benign Disease causing c.3322C>T p.R1108C Reduced ATP binding26 C65 Deleterious Probably damaging Disease causing c.4102C>T p.R1368C C65 Deleterious Probably damaging Disease causing c.4462T>C p.C1488R C65 Deleterious Possibly damaging Disease causing c.4469G>A p.C1490Y Misfolding, mislocali- zation27 C65 Deleterious Probably damaging Disease causing Cryptic donor strongly activated c.4926C>G p.S1642R C25 Deleterious Benign Disease causing c.6079C>T p.L2027F Reduced ATP binding26,29 C15 Deleterious Probably damaging Disease causing c.6089G>A p.R2030Q C35 Deleterious Probably damaging Disease causing c.6229C>T p.R2077W Reduced ATP binding26 C65 Deleterious Probably damaging Disease causing Deletion/frame-shift/stop variants c.666_678del p.K223_ R226delfs c.2041C>T p.R681* c.2408delG p.G803fs c.4234C>T p.Q1412* c.5041_5055del p.V1681_ C1685del c.5169C>G p.Y1723* Splicing affecting variants c.3191-2A>G Predicted change at acceptor site 2 bps downstream: 100% c.3329-2A>G Predicted change at acceptor site 2 bps downstream: 100% c.4667&#fe;2T>C Predicted change at donor site 2 bps upstream: 100% generalized choriocapillaris dystrophy have the occasional hallmarks of early Stargardt disease, such as vermillion fundus, fundus hyperautofluorescence, and a dark choroid on fluorescein angiograms. Login to comment

[hide] Molecular diagnostic testing by eyeGENE: analysis ... Invest Ophthalmol Vis Sci. 2014 Jul 31;55(9):5510-21. doi: 10.1167/iovs.14-14359. Alapati A, Goetz K, Suk J, Navani M, Al-Tarouti A, Jayasundera T, Tumminia SJ, Lee P, Ayyagari R
Molecular diagnostic testing by eyeGENE: analysis of patients with hereditary retinal dystrophy phenotypes involving central vision loss.
Invest Ophthalmol Vis Sci. 2014 Jul 31;55(9):5510-21. doi: 10.1167/iovs.14-14359., [PMID:25082885]

Abstract [show]
PURPOSE: To analyze the genetic test results of probands referred to eyeGENE with a diagnosis of hereditary maculopathy. METHODS: Patients with Best macular dystrophy (BMD), Doyne honeycomb retinal dystrophy (DHRD), Sorsby fundus dystrophy (SFD), or late-onset retinal degeneration (LORD) were screened for mutations in BEST1, EFEMP1, TIMP3, and CTRP5, respectively. Patients with pattern dystrophy (PD) were screened for mutations in PRPH2, BEST1, ELOVL4, CTRP5, and ABCA4; patients with cone-rod dystrophy (CRD) were screened for mutations in CRX, ABCA4, PRPH2, ELOVL4, and the c.2513G>A p.Arg838His variant in GUCY2D. Mutation analysis was performed by dideoxy sequencing. Impact of novel variants was evaluated using the computational tool PolyPhen. RESULTS: Among the 213 unrelated patients, 38 had BMD, 26 DHRD, 74 PD, 8 SFD, 6 LORD, and 54 CRD; six had both PD and BMD, and one had no specific clinical diagnosis. BEST1 variants were identified in 25 BMD patients, five with novel variants of unknown significance (VUS). Among the five patients with VUS, one was diagnosed with both BMD and PD. A novel EFEMP1 variant was identified in one DHRD patient. TIMP3 novel variants were found in two SFD patients, PRPH2 variants in 14 PD patients, ABCA4 variants in four PD patients, and p.Arg838His GUCY2D mutation in six patients diagnosed with dominant CRD; one patient additionally had a CRX VUS. ABCA4 mutations were identified in 15 patients with recessive CRD. CONCLUSIONS: Of the 213 samples, 55 patients (26%) had known causative mutations, and 13 (6%) patients had a VUS that was possibly pathogenic. Overall, selective screening for mutations in BEST1, PRPH2, and ABCA4 would likely yield the highest success rate in identifying the genetic basis for macular dystrophy phenotypes. Because of the overlap in phenotypes between BMD and PD, it would be beneficial to screen genes associated with both diseases.

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39 Mutations and Unknown Variants Detected in Patients With Central Vision Loss Patient Gene Exon DNA Change Protein Change Genotype Result PolyPhen Description PolyPhen Score Molecular Diagnosis Late-onset retinal degeneration NA CTRP5 NA NA NA NA NA NA Sorsby fundus dystrophy Patient 1 TIMP3 1 c.113C>G p.Ser38Cys Het vAR/us Probably damaging 1 Positive Patient 2 TIMP3 1 c.113C>G p.Ser38Cys Het vAR/us Probably damaging 1 Positive Patient 3 TIMP3 5 c.610A>T p.Ser204Cys Het Mut Positive Doyne honeycomb dystrophy Patient 1 EFEMP1 9 c.1033C>T p.Arg345Trp Het Mut Positive Patient 2 EFEMP1 9 c.1033C>T p.Arg345Trp Het Mut Positive Patient 3 EFEMP1 IVS10 c.IVS10-14C>T None Het vAR/us NA NA Unconfirmed Best macular dystrophy Patient 1 BEST1 2 c.28G>A p.Ala10Thr Het Mut Positive Patient 2 BEST1 2 c.47C>T p.Ser16Phe Het Mut Positive Patient 3 BEST1 2 c.72G>T p.Trp24Cys Het Mut Positive Patient 4 BEST1 3 c.240C>A p.Phe80Leu Het Mut Positive Patient 5 BEST1 3 c.240C>A p.Phe80Leu Het Mut Positive Patient 6 BEST1 4 c.248G>C p.Gly83Ala Het vAR/us Probably damaging 1 Positive Patient 7 BEST1 4 c.277T>C p.Trp93Arg Het vAR/us Probably damaging 1 Positive Patient 8 BEST1 4 c.279G>C p.Trp93Cys Het Mut Positive Patient 9 BEST1 6 c.652C>T p.Arg218Cys Het Mut Positive Patient 10 BEST1 6 c.652C>T p.Arg218Cys Het Mut Positive Patient 11 BEST1 6 c.680A>G p.Tyr227Cys Het Mut Positive Patient 12 BEST1 6 c.741G>A p.Arg218His Het Mut Positive Patient 13 BEST1 6 c.741G>A p.Arg218His Het Mut Positive Patient 14 BEST1 7 c.727G>A p.Ala243Thr Het Mut Positive Patient 15 BEST1 7 c.727G>A p.Ala243Thr Het Mut Positive Patient 16 BEST1 7 c.728C>T p.Ala243Val Het Mut Positive Patient 17 BEST1 7 c.728C>T p.Ala243Val Het Mut Positive Patient 18 BEST1 8 c.880C>T p.Leu294Phe Het vAR/us Probably damaging 1 Positive Patient 19 BEST1 8 c.887A>G p.Asn296Ser Het Mut Positive Patient 20 BEST1 8 c.903T>G p.Asp301Glu Het Mut Positive Patient 21 BEST1 8 c.903T>G p.Asp301Glu Het Mut Positive Patient 22 BEST1 8 c.910G>A p.Asp304Asn Het Mut Positive Patient 23 BEST1 8 c.925T>C p.Trp309Arg Het vAR/us Probably damaging 1 Positive Patient 24 BEST1 8 c.929T>C p.Ile310Thr Het Mut Positive Patient 25, case 3 BEST1 4 c.250T>G p.Phe84Val Het vAR/us Probably damaging 1 Positive Pattern dystrophy Patient 1 ABCA4 6 c.634C>T p.Arg212Cys Het Mut Positive ABCA4 30 c.4469G>A p.Cys1490Tyr Het Mut Patient 2 ABCA4 17 c.2588G>C p.Gly863Ala Het Mut Unconfirmed Patient 3 ABCA4 IVS26 c.3862&#fe;3A>G Abnormal splicing Het vAR/us Unconfirmed Patient 4 PRPH2 1 c.271T>A p.Tyr91Asn Het vAR/us Probably damaging 0.909 Positive PRPH2 1 c.310-313del(AT) p.Ile104Val Het Mut Patient 5, case 6 PRPH2 1 c.422A>G p.Tyr141Cys Het Mut Positive Patient 6 PRPH2 1 c.422A>G p.Tyr141Cys Het Mut Positive Patient 7 PRPH2 1 c.515G>A p.Arg172Gln Het Mut Positive Patient 8 PRPH2 2 c.583C>T p.Arg195Stop Het Mut Positive Patient 9 PRPH2 2 c.629C>G p.Pro210Arg Het Mut Positive Patient 10 PRPH2 2 c.635G>C p.Ser212Thr Het Mut Positive Patient 11 PRPH2 2 c.683C>T p.Thr228Ile Het Mut Positive Patient 12 PRPH2 2 c.708C>G p.Tyr236Stop Het Mut Positive Patient 13, case 4 PRPH2 IVS2 c.828&#fe;3A>T Splice Het Mut Positive TABLE 2. Continued Patient Gene Exon DNA Change Protein Change Genotype Result PolyPhen Description PolyPhen Score Molecular Diagnosis Patient 14 PRPH2 IVS2 c.828&#fe;3A>T Splice Het Mut Positive Patient 15 PRPH2 IVS2 c.828&#fe;3A>T Splice Het Mut Positive Patient 16 PRPH2 IVS2 c.828&#fe;3A>T Splice Het Mut Positive Patient 17, case 2 ABCA4 IVS38 c.5461-10T>C None Het Mut Unconfirmed Patient 18 PRPH2 2 c.584G>A p.Arg195Gln Het vAR/us Probably damaging 1 Positive Cone-rod dystrophy Patient 1, dominant GUCY2D 13 c.2512C>T p.Arg838Cys Het Mut Positive Patient 2, dominant GUCY2D 13 c.2513G>A p.Arg838His Het Mut Positive Patient 3, dominant GUCY2D 13 c.2513G>A p.Arg838His Het Mut Positive Patient 4, dominant GUCY2D 13 c.2513G>A p.Arg838His Het Mut Positive Patient 5, dominant GUCY2D 13 c.2513G>A p.Arg838His Het Mut Positive CRX 3 c.607T>C p.Ser213Pro Het vAR/us Probably damaging 0.999 Patient 6, recessive ABCA4 2 c.156T>G p.His52Gln Het vAR/us Probably damaging 0.998 Positive ABCA4 3 c.161G>A p.Cys54Tyr Het Mut ABCA4 28 c.4169T>C p.Leu1390Pro Het Mut Patient 7, recessive ABCA4 16 c.2385C>T p.Ser795Arg Het vAR/us Probably damaging 0.99 Positive ABCA4 IVS40 c.5714&#fe;5G>A Splice Het Mut Patient 8, recessive ABCA4 42 c.5882G>A p.Gly1961Glu Het Mut Positive ABCA4 45 c.6221G>T p.Gly2074Val Het vAR/us Probably damaging 1 Patient 9, recessive ABCA4 IVS42 c.5898&#fe;1G<A Splice Het Mut Positive ABCA4 IVS42 c.5899-2delA Splice Het Mut Patient 10, recessive ABCA4 5 c.559C>T p.Arg187Cys Het Mut Positive ABCA4 40 c.5645T>C p.Met1882Thr Het Mut Patient 11, recessive ABCA4 6 c.768G>T p.Val256Val (abnlspl) Het Mut Positive ABCA4 31 c.4577C>T p.Thr1526Met Het Mut Patient 12, recessive ABCA4 12 c.1622T>C p.Leu541Pro Het Mut Positive ABCA4 21 c.3113C>T p.Ala1038Val Het Mut ABCA4 12 c.1622T>C p.Leu541Pro Hom Mut ABCA4 21 c.3113C>T p.Ala1038Val Hom Mut ABCA4 22 c.3322C>T p.Arg1108Cys Het Mut Patient 13, recessive ABCA4 12 c.1622T>C p.Leu541Pro Hom Mut Positive ABCA4 21 c.3113C>T p.Ala1038Val Hom Mut Patient 14, recessive ABCA4 13 c.1927G>A p.Val643Met Het Mut Positive ABCA4 24 c.3602T>G p.Leu1201Arg Het Mut ABCA4 36 c.5186T>C p.Leu1729Pro Het Mut Patient 15, recessive ABCA4 23 c.3364G>A p.Glu1122Lys Het Mut Positive ABCA4 48 c.6529G>A p.Asp2177Asn Het Mut Patient 16, recessive ABCA4 35 c.4918C>T p.Arg1640Trp Het Mut Positive ABCA4 28 c.4222T>C p.Trp1408Arg Het Mut Patient 17, recessive ABCA4 11 c.1532G>A p.Arg511His Het Mut Unconfirmed Patient 18, recessive ABCA4 27 c.3899G>A p.Arg1300Gln Het vAR/us Benign 0.143 Unconfirmed Patient 19, recessive ABCA4 13 c.1933G>A p.Asp645Asn Het Mut Unconfirmed Patient 20, recessive ABCA4 35 c.4918C>T p.Arg1640Trp Het Mut Unconfirmed Patient 21, recessive ABCA4 IVS7 c.859-9T>C Unknown Hom vAR/us NA NA Unconfirmed Molecular Diagnostic Testing by eyeGENE IOVS j September 2014 j Vol. 55 j No. 9 j were screened for the p.Arg838His mutation in GUCY2D, and mutations in the CRX, ELOVL4, PRPH2, and/or ABCA4 genes. 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116 Mutations or Unknown Variants Detected in Patients With Central Vision Loss Gene Exon DNA Change Protein Change Genotype Result PolyPhen Description PolyPhen Score Frequency* Variant ID Late-onset retinal degeneration CTRP5 NA NA NA NA NA NA NA NA NA Sorsby fundus dystrophy TIMP3 1 c.113C>G p.Ser38Cys Het vAR/us Probably damaging 1 2 TIMP3 5 c.610A>T p.Ser204Cys Het Mut 1 CM941325/ rs137853298 Doyne honeycomb dystrophy EFEMP1 9 c.1033C>T p.Arg345Trp Het Mut 2 CM990504 EFEMP1 IVS10 c.IVS10-14C>T None Het vAR/us NA NA 1 Best macular dystrophy BEST1 2 c.28G>A p.Ala10Thr Het Mut 1 CM982017 BEST1 2 c.47C>T p.Ser16Phe Het Mut 1 CM010520 BEST1 2 c.72G>T p.Trp24Cys Het Mut 1 CM982018 BEST1 3 c.240C>A p.Phe80Leu Het Mut 2 CM004423 BEST1 4 c.248G>C p.Gly83Ala Het vAR/us Probably damaging 1 1 BEST1 4 c.277T>C p.Trp93Arg Het vAR/us Probably damaging 1 1 BEST1 4 c.279G>C p.Trp93Cys Het Mut 1 rs28940273/ CM982021 BEST1 6 c.652C>T p.Arg218Cys Het Mut 2 CM982023 BEST1 6 c.680A>G p.Tyr227Cys Het Mut 1 CM982024 BEST1 6 c.741G>A p.Arg218His Het Mut 2 CM003486 BEST1 7 c.727G>A p.Ala243Thr Het Mut 2 CM004434 BEST1 7 c.728C>T p.Ala243Val Het Mut 2 rs28940570/ CM00841 BEST1 8 c.880C>T p.Leu294Phe Het vAR/us Probably damaging 1 1 BEST1 8 c.887A>G p.Asn296Ser Het Mut 1 CM010524 BEST1 8 c.903T>G p.Asp301Glu Het Mut 2 CM991243 BEST1 8 c.910G>A p.Asp304Asn Het Mut 1 CM024219 BEST1 8 c.925T>C p.Trp309Arg Het vAR/us Probably damaging 1 1 BEST1 8 c.929T>C p.Ile310Thr Het Mut 1 CM000843 BEST1 4 c.250T>G p.Phe84Val Het vAR/us Probably damaging 1 1 Pattern dystrophy ABCA4 6 c.634C>T p.Arg212Cys Het Mut 1 rs61750200 ABCA4 17 c.2588G>C p.Gly863Ala Het Mut 1 CM970003/ rs76157638 ABCA4 IVS26 c.3862&#fe;3A>G Abnormal splicing Het vAR/us 1 NA ABCA4 30 c.4469G>A p.Cys1490Tyr Het Mut 1 CM990056/ rs61751402 ABCA4 IVS38 c.5461-10T>C None Het Mut 1 CS057513 PRPH2 1 c.271T>A p.Tyr91Asn Het vAR/us Probably damaging .909 1 PRPH2 1 c.310-313del(AT) p.Ile104Val Het Mut 1 NA/Deletion PRPH2 1 c.422A>G p.Tyr141Cys Het Mut 2 CM010125/ rs61755781 PRPH2 1 c.515G>A p.Arg172Gln Het Mut 1 CM930637/ rs61755792 PRPH2 2 c.583C>T p.Arg195Stop Het Mut 1 CM032999 PRPH2 2 c.629C>G p.Pro210Arg Het Mut 1 CM941210 PRPH2 2 c.635G>C p.Ser212Thr Het Mut 1 CM971289/ rs61755801 PRPH2 2 c.683C>T p.Thr228Ile Het Mut 1 TMP_ESP_6_ 42672248 PRPH2 2 c.708C>G p.Tyr236Stop Het Mut 1 rs61755813 PRPH2 IVS2 c.828&#fe;3A>T Splice Het Mut 4 CS010139 PRPH2 2 c.584G>A p.Arg195Gln Het vAR/us Probably damaging 1 1 TABLE 3. Continued Gene Exon DNA Change Protein Change Genotype Result PolyPhen Description PolyPhen Score Frequency* Variant ID Cone-rod dystrophy ABCA4 2 c.156T>G p.His52Gln Het vAR/us Probably damaging 0.998 1 ABCA4 3 c.161G>A p.Cys54Tyr Het Mut 1 CM990012/ rs150774447 ABCA4 28 c.4169T>C p.Leu1390Pro Het Mut 1 CM014810/ rs61752430 ABCA4 16 c.2385C>T p.Ser795Arg Het vAR/us Probably damaging 0.99 1 ABCA4 IVS40 c.5714&#fe;5G>A Splice Het Mut 1 CS982057 ABCA4 27 c.3899G>A p.Arg1300Gln Het vAR/us Benign 0.143 1 ABCA4 32 c.4661A>G p.Glu1554Gly Het vAR/us Benign 0.326 1 ABCA4 30 c.4383G>A p.Trp1461Stop Het Mut 1 Stop/NA ABCA4 IVS38 c.5461-10T>C None Het Mut NA NA 2 CS057513 ABCA4 22 c.3259G>A p.Glu1087Lys Het Mut 1 CM970008/ rs61751398 ABCA4 42 c.5882G>A p.Gly1961Glu Het Mut 2 CM970016/ rs1800553 ABCA4 45 c.6221G>T p.Gly2074Val Het vAR/us Probably damaging 1 1 ABCA4 IVS42 c.5898&#fe;1G<A Splice Het Mut 1 CS011524 ABCA4 IVS42 c.5899-2delA Splice Het Mut 1 rs3112831 CRX 3 c.607T>C p.Ser213Pro Het vAR/us Probably damaging 0.999 1 ABCA4 5 c.559C>T p.Arg187Cys Het Mut 1 COSM913472 ABCA4 40 c.5645T>C p.Met1882Thr Het Mut 1 rs4147830 ABCA4 6 c.768G>T p.Val256Val (abnlspl) Het Mut 1 CM990057/ rs61750152 ABCA4 31 c.4577C>T p.Thr1526Met Het Mut 1 rs62645944 ABCA4 11 c.1532G>A p.Arg511His Het Mut 1 rs140482171 ABCA4 12 c.1622T>C p.Leu541Pro Het Mut 1 CM990022/ rs61751392 ABCA4 21 c.3113C>T p.Ala1038Val Het Mut 1 CM970006/ rs61751374 ABCA4 12 c.1622T>C p.Leu541Pro Hom Mut 2 CM990022/ rs61751392 ABCA4 21 c.3113C>T p.Ala1038Val Hom Mut 2 CM970006/ rs61751374 ABCA4 22 c.3322C>T p.Arg1108Cys Het Mut 1 CM990039/ rs61750120 ABCA4 13 c.1927G>A p.Val643Met Het Mut 1 CM014293/ rs61749417/ rs143548435 ABCA4 24 c.3602T>G p.Leu1201Arg Het Mut 1 CM990042/ rs61750126 ABCA4 36 c.5186T>C p.Leu1729Pro Het Mut 1 CM990062/ rs61750567 ABCA4 13 c.1933G>A p.Asp645Asn Het Mut 1 rs617494181933 ABCA4 23 c.3364G>A p.Glu1122Lys Het Mut 1 CM990041 ABCA4 48 c.6529G>A p.Asp2177Asn Het Mut 1 CM970023/ rs1800555 ABCA4 35 c.4918C>T p.Arg1640Trp Het Mut 2 CM983728/ rs61751404 ABCA4 28 c.4222T>C p.Trp1408Arg Het Mut 1 CM990048/ rs61750135 GUCY2D 13 c.2512C>T p.Arg838Cys Het Mut 1 rs61750172 GUCY2D 13 c.2513G>A p.Arg838His Het Mut 5 CM012606/ rs61750173 ABCA4 IVS7 c.859-9T>C Unknown Hom vAR/us NA NA 1 ABCA4 42 c.5882G>A p.Gly1961Glu Hom Mut 1 CM970016/ rs1800553 ABCA4 43 c.5917delG Deletion Hom Mut 1 RISN_ABCR: c.5917delG Molecular Diagnostic Testing by eyeGENE IOVS j September 2014 j Vol. 55 j No. 9 j Six patients with late-onset retinal pathology and drusen had well-characterized clinical data. 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[hide] Quantitative fundus autofluorescence distinguishes... Ophthalmology. 2015 Feb;122(2):345-55. doi: 10.1016/j.ophtha.2014.08.017. Epub 2014 Oct 3. Duncker T, Tsang SH, Lee W, Zernant J, Allikmets R, Delori FC, Sparrow JR
Quantitative fundus autofluorescence distinguishes ABCA4-associated and non-ABCA4-associated bull's-eye maculopathy.
Ophthalmology. 2015 Feb;122(2):345-55. doi: 10.1016/j.ophtha.2014.08.017. Epub 2014 Oct 3., [PMID:25283059]

Abstract [show]
PURPOSE: Quantitative fundus autofluorescence (qAF) and spectral-domain optical coherence tomography (SD OCT) were performed in patients with bull's-eye maculopathy (BEM) to identify phenotypic markers that can aid in the differentiation of ABCA4-associated and non-ABCA4-associated disease. DESIGN: Prospective cross-sectional study at an academic referral center. SUBJECTS: Thirty-seven BEM patients (age range, 8-60 years) were studied. All patients exhibited a localized macular lesion exhibiting a smooth contour and qualitatively normal-appearing surrounding retina without flecks. Control values consisted of previously published data from 277 healthy subjects (374 eyes; age range, 5-60 years) without a family history of retinal dystrophy. METHODS: Autofluorescence (AF) images (30 degrees , 488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The grey levels (GLs) from 8 circularly arranged segments positioned at an eccentricity of approximately 7 degrees to 9 degrees in each image were calibrated to the reference (0 GL), magnification, and normative optical media density to yield qAF. In addition, horizontal SD OCT images through the fovea were obtained. All patients were screened for ABCA4 mutations using the ABCR600 microarray, next-generation sequencing, or both. MAIN OUTCOME MEASURES: Quantitative AF, correlations between AF and SD OCT, and genotyping for ABCA4 variants. RESULTS: ABCA4 mutations were identified in 22 patients, who tended to be younger (mean age, 21.9+/-8.3 years) than patients without ABCA4 mutations (mean age, 42.1+/-14.9 years). Whereas phenotypic differences were not obvious on the basis of qualitative fundus AF and SD OCT imaging, with qAF, the 2 groups of patients were clearly distinguishable. In the ABCA4-positive group, 37 of 41 eyes (19 of 22 patients) had qAF8 of more than the 95% confidence interval for age. Conversely, in the ABCA4-negative group, 22 of 26 eyes (13 of 15 patients) had qAF8 within the normal range. CONCLUSIONS: The qAF method can differentiate between ABCA4-associated and non-ABCA4-associated BEM and may guide clinical diagnosis and genetic testing.

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66 [L541P; A1038V] 438 432 16 M 25 White 0.60 0.60 p.S84fs p.R2107H 294 17 F 24 Black 0.70 0.88 p.G991R p.L1138P 321 326 18 M 26 White 0.00y 0.00y p.R1300* p.R2106C 419 412 19 M 11 White 0.40z 0.40z p.W821R p.C2150Y 304 296 20 F 16 White 0.70 0.40 p.K1547* p.R2030Q 481 513 21 F 13 White 1.30 1.00 pR1108C p.Q1412* 511 528 22 F 18 White 0.00 0.00 p.G863A c.5898&#fe;1G/A 465 431 Mutations in Other Genes 23 F 16 White 0.40 0.48 GUCY2D e p.R838H 152 165 24 M 53 Black 0.88 0.88 CNGA3 e p. Login to comment
170 This is illustrated in Figure 8, in which disease progression over 2.5 years is shown for the brother of patient 15, who also carries the complex allele L541P/ A1038V. Login to comment
187 This ABCA4-positive patient was not included in the study (because of presence of peripheral flecks), but he also carries the complex allele L541P/A1038V. Login to comment

[hide] Structural and genetic assessment of the ABCA4-ass... Invest Ophthalmol Vis Sci. 2014 Oct 9;55(11):7217-26. doi: 10.1167/iovs.14-14674. Noupuu K, Lee W, Zernant J, Tsang SH, Allikmets R
Structural and genetic assessment of the ABCA4-associated optical gap phenotype.
Invest Ophthalmol Vis Sci. 2014 Oct 9;55(11):7217-26. doi: 10.1167/iovs.14-14674., [PMID:25301883]

Abstract [show]
PURPOSE: To investigate the developmental stages and genetic etiology of the optical gap phenotype in recessive Stargardt disease (STGD1). METHODS: Single and longitudinal data points from 15 patients, including four sibling pairs, exhibiting an optical gap phenotype on spectral-domain optical coherence tomography (SD-OCT) with confirmed disease-causing ABCA4 alleles were retrospectively analyzed. Fundus images with corresponding SD-OCT scans were collected with a confocal scanning laser ophthalmoscope. Structural phenotypes were assigned to three developmental stages according to SD-OCT. The ABCA4 gene was screened in all patients. RESULTS: At least two disease-causing ABCA4 variants where identified in each patient; all except one (91%) were compound heterozygous for the p.G1961E mutation. All patients exhibited structural findings on SD-OCT that grouped into three progressive developmental stages over several years. Stage 1 was characterized by mild disruptions of the ellipsoid zone (EZ) band over the fovea. Stage 2 was a progressive expansion of the EZ band loss resulting in an empty lesion devoid of photoreceptors. Stage 3 observed a structural collapse of the inner retinal layers into the optical gap space leading to involvement and atrophy of the RPE thereafter. CONCLUSIONS: The optical gap phenotype in STGD1 can be structurally divided into three progressive stages spanning several years. This particular phenotype also appears to be highly associated with the p.G1961E mutation of ABCA4. Taken together, it appears that a focal loss of photoreceptors sequentially precedes RPE dysfunction in the early development of ABCA4-associated optical gap lesions.

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186 Of the other disease-associated ABCA4 alleles compound heterozygous with p.G1961E, the p.L541P mutation, presenting alone or as a complex allele with the p.A1038V variant, was observed in seven cases (four unrelated) with optical gap (Table 2 and Supplementary Table S1) while only once in patients without the phenotype (Supplementary Table S1). Login to comment
189 Therefore, we can conclude that the p.G1961E variant, maybe sometimes together with the p.L541P or p. (L541P; A1038V) allele, is currently the only ABCA4 mutation associated with the optical gap phenotype. Login to comment

[hide] Foveal sparing in Stargardt disease. Invest Ophthalmol Vis Sci. 2014 Oct 16;55(11):7467-78. doi: 10.1167/iovs.13-13825. van Huet RA, Bax NM, Westeneng-Van Haaften SC, Muhamad M, Zonneveld-Vrieling MN, Hoefsloot LH, Cremers FP, Boon CJ, Klevering BJ, Hoyng CB
Foveal sparing in Stargardt disease.
Invest Ophthalmol Vis Sci. 2014 Oct 16;55(11):7467-78. doi: 10.1167/iovs.13-13825., [PMID:25324290]

Abstract [show]
PURPOSE: To provide a clinical and genetic description of a patient cohort with Stargardt disease (STGD1) with identifiable foveal sparing. METHODS: Patients with retinal atrophy (defined as an absence of autofluorescence) that surrounded the fovea by at least 180 degrees and did not include the fovea were defined as having foveal sparing; eyes with visual acuity (VA) worse than 20/200 were excluded. We reviewed the medical files and extracted data regarding medical history, VA, ophthalmoscopy, static perimetry, fundus photography, spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography (FA), fundus autofluorescence (FAF), and electroretinography (ERG). We screened each patient's ABCA4 gene for mutations. RESULTS: Seventeen eyes with foveal sparing were identified in 13 unrelated patients. In 4 eyes, the fovea gradually became atrophic after the initial foveal sparing. The mean age at onset was 51 years (range, 32-67 years). Visual acuity was 20/40 or better in all foveal sparing eyes and was 20/25 or better in 41%. Fundus autofluorescence imaging revealed hyperautofluorescent flecks and parafoveal retinal atrophy; SD-OCT revealed sharply delineated atrophy; and perimetry revealed parafoveal scotomas with intact foveal sensitivity. Finally, genetic screening identified mutations in 19 of the 26 ABCA4 gene alleles. CONCLUSIONS: Foveal sparing occurs mainly in patients with late-onset STGD1 and represents the milder end of the clinical spectrum in STGD1. The anatomy, metabolism, and biochemistry of the retina, as well as genetic variations in genes other than ABCA4, can influence the etiology of foveal sparing. Identifying these fovea-protecting factors will facilitate the future development of strategies designed to treat STGD1.

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114 ABCA4 Mutations in STGD1 Patients With Foveal Sparing Allele 1 Allele 2 References DNA Variant Effect DNA Variant Effect P1 c.5461-10TC Unknown NI NA 35, 36 P2 c.3113CT p.Ala1038Val c.3874CT p.Gln1292* 16, 37, 38, 58 P3 c.5461-10TC Unknown c.5537TC p.Ile1846Thr 23, 35, 39, 58 P4 c.4363TC p.Cys1455Arg NI NA 40 P5 c.1822TA p.Phe608Ile c.4685TC p.Ile1562Thr 23, 40, 41, 59 P6 c.768GT Splice defect c.3113CT p.Ala1038Val 16, 23, 37 P7 c.5196&#fe;1GT Splice defect NI NA 45, 58 P8 c.3874CT p.Gln1292* NI NA 38 P9 c.5461-10TC Unknown NI NA 35, 58 P10 c.1822TA p.Phe608Ile NI NA 23, 41 P11 c.286AG p.Asn96Asp NI NA 43 P12 c.1805GA p.Arg602Gln c.4462TC p.Cys1488Arg 37, 39, 42-44 P13 c.3874CT p.Gln1292* c.1928TG p.Val643Gly 38, 45 NI, not identified; NA, not applicable. Login to comment
151 ABCA4 Mutations in STGD1 Patients With Foveal Sparing Allele 1 Allele 2 References DNA Variant Effect DNA Variant Effect P1 c.5461-10TC Unknown NI NA 35, 36 P2 c.3113CT p.Ala1038Val c.3874CT p.Gln1292* 16, 37, 38, 58 P3 c.5461-10TC Unknown c.5537TC p.Ile1846Thr 23, 35, 39, 58 P4 c.4363TC p.Cys1455Arg NI NA 40 P5 c.1822TA p.Phe608Ile c.4685TC p.Ile1562Thr 23, 40, 41, 59 P6 c.768GT Splice defect c.3113CT p.Ala1038Val 16, 23, 37 P7 c.5196&#fe;1GT Splice defect NI NA 45, 58 P8 c.3874CT p.Gln1292* NI NA 38 P9 c.5461-10TC Unknown NI NA 35, 58 P10 c.1822TA p.Phe608Ile NI NA 23, 41 P11 c.286AG p.Asn96Asp NI NA 43 P12 c.1805GA p.Arg602Gln c.4462TC p.Cys1488Arg 37, 39, 42-44 P13 c.3874CT p.Gln1292* c.1928TG p.Val643Gly 38, 45 NI, not identified; NA, not applicable. Login to comment

[hide] Correlations among near-infrared and short-wavelen... Invest Ophthalmol Vis Sci. 2014 Oct 23;55(12):8134-43. doi: 10.1167/iovs.14-14848. Duncker T, Marsiglia M, Lee W, Zernant J, Tsang SH, Allikmets R, Greenstein VC, Sparrow JR
Correlations among near-infrared and short-wavelength autofluorescence and spectral-domain optical coherence tomography in recessive Stargardt disease.
Invest Ophthalmol Vis Sci. 2014 Oct 23;55(12):8134-43. doi: 10.1167/iovs.14-14848., [PMID:25342616]

Abstract [show]
PURPOSE: Short-wavelength (SW) fundus autofluorescence (AF) is considered to originate from lipofuscin in retinal pigment epithelium (RPE) and near-infrared (NIR) AF from melanin. In patients with recessive Stargardt disease (STGD1), we correlated SW-AF and NIR-AF with structural information obtained by spectral-domain optical coherence tomography (SD-OCT). METHODS: Twenty-four STGD1 patients (45 eyes; age 8 to 61 years) carrying confirmed disease-associated ABCA4 mutations were studied prospectively. Short-wavelength AF, NIR-AF, and SD-OCT images were acquired. RESULTS: Five phenotypes were identified according to features of the central lesion and extent of fundus change. Central zones of reduced NIR-AF were typically larger than areas of diminished SW-AF and reduced NIR-AF usually approximated areas of ellipsoid zone (EZ) loss identified by SD-OCT (group 1; r, 0.93, P < 0.0001). In patients having a central lesion with overlapping parafoveal rings of increased NIR-AF and SW-AF (group 3), the extent of EZ loss was strongly correlated with the inner diameter of the NIR-AF ring (r, 0.89, P < 0.0001) and the eccentricity of the outer border of the NIR-AF ring was greater than that of the SW-AF ring. CONCLUSIONS: Lesion areas were more completely delineated in NIR-AF images than with SW-AF. In most cases, EZ loss was observed only at locations where NIR-AF was reduced or absent, indicating that RPE cell atrophy occurs in advance of photoreceptor cell degeneration. Because SW-AF was often increased within the central area of EZ disruption, degenerating photoreceptor cells may produce lipofuscin at accelerated levels. Consideration is given to mechanisms underlying hyper-NIR-AF in conjunction with increased SW-AF.

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167 Interestingly, these patients were the youngest in our cohort and all carried the complex allele L541P/A1038V. Login to comment
168 The latter mutations are located in the exocytoplasmic domain-1 and nucleotide binding domain-1 and confer severe and relatively early-onset retina-wide disease.37-40 In recent work using quantitative fundus AF, we also reported that the L541P/ A1038V complex allele confers particularly high levels of fundus AF.4 At positions where EZ is disrupted, the NIR-AF signal may be detectable even if the RPE cells are dysfunctional. Alternatively, this pattern could indicate that in these cases photoreceptor cells die first. Login to comment

[hide] Early-onset stargardt disease: phenotypic and geno... Ophthalmology. 2015 Feb;122(2):335-44. doi: 10.1016/j.ophtha.2014.08.032. Epub 2014 Oct 17. Lambertus S, van Huet RA, Bax NM, Hoefsloot LH, Cremers FP, Boon CJ, Klevering BJ, Hoyng CB
Early-onset stargardt disease: phenotypic and genotypic characteristics.
Ophthalmology. 2015 Feb;122(2):335-44. doi: 10.1016/j.ophtha.2014.08.032. Epub 2014 Oct 17., [PMID:25444351]

Abstract [show]
OBJECTIVE: To describe the phenotype and genotype of patients with early-onset Stargardt disease. DESIGN: Retrospective cohort study. PARTICIPANTS: Fifty-one Stargardt patients with age at onset </=10 years. METHODS: We reviewed patient medical records for age at onset, medical history, initial symptoms, best-corrected visual acuity (BCVA), ophthalmoscopy, fundus photography, fundus autofluorescence (FAF), fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), and full-field electroretinography (ffERG). The ABCA4 gene was screened for mutations. MAIN OUTCOME MEASURES: Age at onset, BCVA, fundus appearance, FAF, FA, SD-OCT, ffERG, and presence of ABCA4 mutations. RESULTS: The mean age at onset was 7.2 years (range, 1-10). The median times to develop BCVA of 20/32, 20/80, 20/200, and 20/500 were 3, 5, 12, and 23 years, respectively. Initial ophthalmoscopy in 41 patients revealed either no abnormalities or foveal retinal pigment epithelium (RPE) changes in 10 and 9 patients, respectively; the other 22 patients had foveal atrophy, atrophic RPE lesions, and/or irregular yellow-white fundus flecks. On FA, there was a "dark choroid" in 21 out of 29 patients. In 14 out of 50 patients, foveal atrophy occurred before flecks developed. On FAF, there was centrifugal expansion of disseminated atrophic spots, which progressed to the eventual profound chorioretinal atrophy. Spectral-domain OCT revealed early photoreceptor damage followed by atrophy of the outer retina, RPE, and choroid. On ffERG in 26 patients, 15 had normal amplitudes, and 11 had reduced photopic and/or scotopic amplitudes at their first visit. We found no correlation between ffERG abnormalities and the rate of vision loss. Thirteen out of 25 patients had progressive ffERG abnormalities. Finally, genetic screening of 44 patients revealed >/=2 ABCA4 mutations in 37 patients and single heterozygous mutations in 7. CONCLUSIONS: In early-onset Stargardt, initial ophthalmoscopy can reveal no abnormalities or minor retinal abnormalities. Yellow-white flecks can be preceded by foveal atrophy and may be visible only on FAF. Although ffERG is insufficient for predicting the rate of vision loss, abnormalities can develop. Over time, visual acuity declines rapidly in parallel with progressive retinal degeneration, resulting in profound chorioretinal atrophy. Thus, early-onset Stargardt lies at the severe end of the spectrum of ABCA4-associated retinal phenotypes.

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137 11 13 16, 23, 32, 39 c.818G>A p.Trp273* 1 1 This study c.872C>T p.Pro291Leu 1 1 34 c.1622T>C p.Leu541Pro 2 2 1, 16, 32, 40 c.1822T>A p.Phe608Ile 4 5 1, 23 c.1957C>T p.Arg653Cys 1 1 32, 41 c.2588G>C p.Gly863Ala/p.DelGly863 3 4 16, 18, 23, 32, 42 c.2919-?_3328&#fe;?del p.Ser974_Gly1110delinsCys 2 2 23 c.2947A>G p.Thr983Ala 3 4 34 c.3113C>T p.Ala1038Val 2 2 16, 31, 32, 40, 43 c.3335C>A p.Thr1112Asn 1 1 23 c.3449G>A p.Cys1150Tyr 1 1 This study c.3813G>C p.Glu1271Asp 1 1 This study c.3874C>T p.Gln1292* 1 1 34 c.4224G>T p.Trp1408Cys 1 1 This study c.4462T>C p.Cys1488Arg 1 1 1, 8, 44, 45 c.4506C>A p.Cys1502* 1 1 34 c.4539&#fe;1G>T p.? Login to comment

[hide] Common synonymous variants in ABCA4 are protective... BMC Ophthalmol. 2015 Mar 6;15:18. doi: 10.1186/s12886-015-0008-0. Grassmann F, Bergholz R, Mandl J, Jagle H, Ruether K, Weber BH
Common synonymous variants in ABCA4 are protective for chloroquine induced maculopathy (toxic maculopathy).
BMC Ophthalmol. 2015 Mar 6;15:18. doi: 10.1186/s12886-015-0008-0., [PMID:25884411]

Abstract [show]
BACKGROUND: Chloroquine (CQ) and hydroxychloroquine (HCQ) are used to treat auto-immune related diseases such as rheumatoid arthritis (RA) or systemic lupus erythematosus. Both drugs however can cause retinal toxicity eventually leading to irreversible maculopathy and retinopathy. Established risk factors are duration and dosage of treatment while the involvement of genetic factors contributing to toxic maculopathy is largely unclear. To address the latter issue, this study aimed to expand on earlier efforts by (1) evaluating risk-altering variants known to be associated with age-related macular degeneration (AMD), a frequent maculopathy in individuals over 55 years of age, and (2) determining the contribution of genetic variants in the coding sequence of the ABCA4 gene. METHODS: The ABCA4 gene was analyzed by deep sequencing technology using a personal genome machine (Ion Torrent) with 200 bp read length. Assessment of AMD variants was done by restriction enzyme digestion of PCR products and TaqMan SNP genotyping. Effect sizes, p-values and confidence intervals of common variants were evaluated by logistic regression (Firth's bias corrected). To account for multiple testing, p-values were adjusted according to the false discovery rate. RESULTS: We found no effects of known AMD-associated variants on the risk of toxic maculopathy. In contrast, we report a statistically significant association of common variants in the ABCA4 gene with retinal disease, assessed by a score-based variance-component test (PSKAT = 0.0055). This association remained significant after adjustment for environmental factors like age and duration of medication and was driven by three common variants in ABCA4 (c.5682G > C, c.5814A > G, c.5844A > G), all conferring a reduced risk for toxic maculopathy. CONCLUSIONS: Our findings demonstrate that minor alleles of common genetic variants in ABCA4 significantly reduce susceptibility to develop toxic maculopathy under CQ treatment. A refined risk profile based on genetic and environmental factors may have implications for revised recommendations in CQ as well as HCQ treatment.

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95 Table 2 Genetic variants identified in ABCA4 sequence analysis in CQ-treated patients with (cases) and without (controls) toxic maculopathy Frequency in Variant (NM_000350.2) Amino acid exchange (NP_000341.2) Cases Controls EURߤ Raw p-value FDR# c.324G > A M114I 0.00 0.04 - - - c.635G > A R212H 0.06 0.08 0.06 - - c.1268A > G* H423R 0.29 0.23 0.30 0.58783 0.58783 c.1269C > T H423H 0.13 0.04 0.07 - - c.1622T > C L541P 0.02 0.00 - - - c.2588G > C G863A 0.00 0.04 0.00 - - c.2828G > A R943Q 0.04 0.12 0.04 - - c.3113C > T A1038V 0.02 0.00 0.00 - - c.4203C > A P1401P 0.00 0.04 - - - c.4297G > A V1433I 0.00 0.04 0.00 - - c.5603A > T N1868I 0.06 0.08 0.07 - - c.5682G > C* L1894L 0.13 0.38 0.26 0.02292 0.030 c.5814A > G* L1938L 0.06 0.31 0.18 0.00722 0.014 c.5843C > T P1948L 0.04 0.08 0.04 - - c.5844A > G* P1948P 0.06 0.31 0.19 0.00722 0.014 c.6069T > C I2023I 0.04 0.08 0.06 - c.6148G > C V2050L 0.02 0.00 0.00 - - c.6249C > T I2083I 0.04 0.08 0.05 - - c.6282 + 7G > A - 0.04 0.08 0.05 - - c.6285T > C D2095D 0.08 0.15 0.10 - - c.6357A > G E2119E 0.02 0.00 - - - c.6730-3T > C - 0.02 0.12 0.02 - - c.6764G > T S2255I 0.02 0.12 0.02 - - *Common variants (combined frequency in cases and controls > 11.6%). Login to comment

[hide] Objective Analysis of Hyperreflective Outer Retina... Invest Ophthalmol Vis Sci. 2015 Jul;56(8):4662-7. doi: 10.1167/iovs.15-16955. Park JC, Collison FT, Fishman GA, Allikmets R, Zernant J, Liu M, McAnany JJ
Objective Analysis of Hyperreflective Outer Retinal Bands Imaged by Optical Coherence Tomography in Patients With Stargardt Disease.
Invest Ophthalmol Vis Sci. 2015 Jul;56(8):4662-7. doi: 10.1167/iovs.15-16955., [PMID:26207301]

Abstract [show]
PURPOSE: To develop and apply an objective algorithm for analyzing outer retinal layers imaged by spectral-domain optical coherence tomography (SD-OCT) in patients with Stargardt disease (STGD1). METHODS: Horizontal macular B-scans were acquired from 20 visually normal controls and 20 genetically confirmed stage 1 STGD1 patients. The number of outer retinal bands was quantified using a semiautomated algorithm that detected bands using the second derivative of longitudinal reflectivity profiles. The present analysis focused on the three outermost bands, currently associated with the ellipsoid zone (EZ), cone outer segment interdigitation zone (IZ), and retinal pigment epithelium (RPE) complex. RESULTS: The RPE complex and EZ bands were detected throughout the B-scan in all controls. The RPE complex was detected throughout the B-scan in all patients, but was atrophic appearing in some locations. The EZ band was detected only outside the central lesion. Interdigitation zone band detection varied as a function of eccentricity for both groups, with detection for controls being highest in the para- and perifovea and lowest in the fovea and near periphery. In patients, the IZ band was generally not present in the fovea or para- or perifovea due to the central lesion. Outside of the lesion, the IZ band was detected in 26% of patients (mean detection across the near periphery), which was approximately half of the detection in controls. CONCLUSIONS: An objective approach for quantifying the number of outer retinal OCT bands found reduced IZ detection in STGD1 patients. This occurred even outside the central lesion, demonstrating an inability to image the IZ, possibly due to enhanced RPE reflectivity or abnormal outer retinal structure.

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52 of ABCA4 Mutations Mutation(s) 1 13 M 20/70 2 p.[(L541P; A1038V)] (;)c.5714&#fe;5G>A 2 15 F 20/60 2 c.3050&#fe;5G>A(;)p.(G1961E) 3 15 F 20/80 2 p.[(R1129L(;)A1773V)] 4 16 F 10/1001 Sister of patient 3 5 20 M 20/160&#fe;2 2 p.[(R1129C(;)R2077W)] 6 20 F 20/1601 2 p.[(G1961E(;)R2040*)] 7 21 M 20/40 2 p.[(R219T(;)W439*(;)G863A)] 8 23 F 10/100 2 c.5461-10T>C(;)p.(G1961E) 9 23 F 20/1001 2 c.302&#fe;1G>A(;)p.(R2107H) 10 28 F 20/1001 2 c.5461-10T>C(;)p.(G1961E) 11 30 F 20/25&#fe;2 1 p.[(R2077W)];[?] Login to comment

[hide] Flecks in Recessive Stargardt Disease: Short-Wavel... Invest Ophthalmol Vis Sci. 2015 Jul;56(8):5029-39. doi: 10.1167/iovs.15-16763. Sparrow JR, Marsiglia M, Allikmets R, Tsang S, Lee W, Duncker T, Zernant J
Flecks in Recessive Stargardt Disease: Short-Wavelength Autofluorescence, Near-Infrared Autofluorescence, and Optical Coherence Tomography.
Invest Ophthalmol Vis Sci. 2015 Jul;56(8):5029-39. doi: 10.1167/iovs.15-16763., [PMID:26230768]

Abstract [show]
PURPOSE: We evaluated the incongruous observation whereby flecks in recessive Stargardt disease (STGD1) can exhibit increased short-wavelength autofluorescence (SW-AF) that originates from retinal pigment epithelium (RPE) lipofuscin, while near-infrared AF (NIR-AF), emitted primarily from RPE melanin, is usually reduced or absent at fleck positions. METHODS: Flecks in SW- and NIR-AF images and spectral-domain optical coherence tomography (SD-OCT) scans were studied in 19 STGD1 patients carrying disease-causing ABCA4 mutations. Fleck spatial distribution and progression were recorded in serial AF images. RESULTS: Flecks observed in SW-AF images typically colocalized with darkened foci in NIR-AF images; the NIR-AF profiles were larger. The decreased NIR-AF signal from flecks preceded apparent changes in SW-AF. Spatiotemporal changes in fleck distribution usually progressed centrifugally, but in one case centripetal expansion was observed. Flecks in SW-AF images corresponded to hyperreflective deposits that progressively traversed photoreceptor-attributable bands in SD-OCT images. Outer nuclear layer (ONL) thickness negatively correlated with expansion of flecks from outer to inner retina. CONCLUSIONS: In the healthy retina, RPE lipofuscin fluorophores form in photoreceptor cells but are transferred to RPE; thus the SW-AF signal from photoreceptor cells is negligible. In STGD1, NIR-AF imaging reveals that flecks are predominantly hypofluorescent and larger and that NIR-AF darkening occurs prior to heightened SW-AF signal. These observations indicate that RPE cells associated with flecks in STGD1 are considerably changed or lost. Spectral-domain OCT findings are indicative of ongoing photoreceptor cell degeneration. The bright SW-AF signal of flecks likely originates from augmented lipofuscin formation in degenerating photoreceptor cells impaired by the failure of RPE.

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48 [IVS15&#fe;1G>A 2 M 12.00 Caucasian 0.5 0.5 p. [L541P; A1038V] 3* M 9.00 Caucasian 1 1 p. [W855*]; [T1526M] 4 F 47.55 Caucasian 1.3 1.3 p. [L541P; A1038V]; [G1961E] 5* F 16.47 Caucasian 0.6 0.6 p. [T972N]; [L2027F] 6* M 16.98 Caucasian 1.3 1.3 p. [K346T]; [T1117I] 7 F 23.80 Caucasian 0.6 0.4 p. [R1161S] 8* F 28.67 Caucasian 1.3 1.3 p. [P1380L]; [P1380L] 9 M 42.83 Caucasian 0.9 0.4 c. Login to comment
49 [571-1G>T 10* M 13.89 Caucasian 0.4 0.4 p. [L541P; A1038V]; [L2027F] 11* F 20.20 Caucasian 0.9 0.9 p. [P1380L]; [G1961E] 12 M 27.61 African-Arab 0 0 p. [R1300*]; [R2106C] 13* M 46.93 Caucasian 0.3 0.4 p. [C1490Y]; [G1961E] 14* M 26.82 Caucasian 0 0 c. Login to comment

[hide] Quantitative Fundus Autofluorescence and Optical C... Invest Ophthalmol Vis Sci. 2015 Nov 1;56(12):7274-85. doi: 10.1167/iovs.15-17371. Duncker T, Stein GE, Lee W, Tsang SH, Zernant J, Bearelly S, Hood DC, Greenstein VC, Delori FC, Allikmets R, Sparrow JR
Quantitative Fundus Autofluorescence and Optical Coherence Tomography in ABCA4 Carriers.
Invest Ophthalmol Vis Sci. 2015 Nov 1;56(12):7274-85. doi: 10.1167/iovs.15-17371., [PMID:26551331]

Abstract [show]
PURPOSE: To assess whether carriers of ABCA4 mutations have increased RPE lipofuscin levels based on quantitative fundus autofluorescence (qAF) and whether spectral-domain optical coherence tomography (SD-OCT) reveals structural abnormalities in this cohort. METHODS: Seventy-five individuals who are heterozygous for ABCA4 mutations (mean age, 47.3 years; range, 9-82 years) were recruited as family members of affected patients from 46 unrelated families. For comparison, 57 affected family members with biallelic ABCA4 mutations (mean age, 23.4 years; range, 6-67 years) and two noncarrier siblings were also enrolled. Autofluorescence images (30 degrees , 488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density to yield qAF. Horizontal SD-OCT scans through the fovea were obtained and the thicknesses of the outer retinal layers were measured. RESULTS: In 60 of 65 carriers of ABCA4 mutations (age range, 9-60), qAF levels were within normal limits (95% confidence level) observed for healthy noncarrier subjects, while qAF levels of affected family members were significantly increased. Perifoveal fleck-like abnormalities were observed in fundus AF images in four carriers, and corresponding changes were detected in the outer retinal layers in SD-OCT scans. Thicknesses of the outer retinal layers were within the normal range. CONCLUSIONS: With few exceptions, individuals heterozygous for ABCA4 mutations and between the ages of 9 and 60 years do not present with elevated qAF. In a small number of carriers, perifoveal fleck-like changes were visible.

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28 [L541P;A1038V] 0.10 0.10 OS n/a 141 S2.2 F 44.4 Indian Mother c.6729&#fe;5_&#fe;19del 0.10 0.00 OS 257 291 S2.3 M 56.2 Indian Father p.G1961E 0.00 0.00 OD 475 431 S3.4 F 54.1 White Mother p.G863A 0.00 0.00 OS 459 451 S3.5 F 82.0 White Grandmother p.G863A 0.00 0.00 OD n/a n/a S4.2 F 44.6 White Mother p.W855* 0.00 0.00 OD 330 n/a S4.3 M 40.9 White Father p.T1526M 0.00 0.00 OS 283 271 S5.2 F 71.5 White Sister p.C698Y 0.00 0.10 OD n/a n/a S5.3 F 67.5 White Sister c.2160&#fe;1G>C 0.00 0.00 OS n/a n/a S5.4 F 62.9 White Sister p.C698Y 0.00 0.00 OD n/a n/a S6.2 M 54.9 Black Brother p.T1526M 0.10 0.00 OS 477 423 S7.2 F 48.9 White Mother c.5196&#fe;1G>A 0.00 0.00 OS 443 415 S8.2 F 59.6 White Mother p.K346T 0.00 0.00 OD 546 483 S8.3 M 54.6 White Father p.T1117I 0.10 0.10 OD 289 n/a S9.2 F 51.5 White Mother c.5196&#fe;1137G>A 0.00 0.00 n/a 302 n/a S9.3 M 57.8 White Father p.C54Y 0.00 0.00 OS 419 375 S10.2 M 24.1 Indian Brother p.Q2220* 0.00 0.00 OD 227 227 S11.2 F 40.0 Asian Mother c.5923del 0.00 0.18 OD 229 191 S11.3 M 40.1 Asian Father p.R408* 0.00 0.00 OD 195 178 S12.2 F 53.2 White Mother p.L2027F 0.00 0.00 n/a 355 309 S13.2 F 49.8 White Mother p.R1161S 0.00 0.00 OS 367 372 S13.3 M 22.3 White Brother p.R1161S 0.00 0.00 OD 202 206 S14.2 F 67.0 White Mother p.P1380L 0.00 0.00 OD n/a n/a S14.3 F 24.4 White Sister p.P1380L 0.00 0.00 OS n/a 163 S15.3 F 26.8 White Sister c.3050&#fe;5G>A 0.00 0.00 n/a 293 281 S16.2 M 53.7 Black Father c.4253&#fe;5G>T 0.00 0.00 n/a n/a 204 S17.2 F 60.0 Hispanic Mother p.A1038V 0.00 0.00 n/a 247 n/a S18.2 F 41.8 Indian Father c.5917del 0.00 0.00 OD n/a 194 S18.3 M 48.6 Indian Mother c.859-9T>C 0.00 0.00 OD 253 215 S18.4 F 12.9 Indian Sister c.5917del 0.00 0.00 OD 84 93 S19.4 F 58.5 White Mother p.L2027F 0.00 0.00 OD 205 n/a S19.5 M 61.6 White Father p.G851D 0.10 0.10 OD n/a n/a S20.2 F 41.5 White Mother c.5312&#fe;1G>A 0.00 0.00 n/a 335 351 S20.3 M 39.0 White Father p.R2030* 0.00 0.10 n/a 442 n/a S21.3 F 53.1 White Mother p.G1961E 0.00 0.00 OD 490 488 S22.3 M 46.3 White Father p.L2027F 0.00 0.00 OS 386 376 S22.4 F 47.1 White Mother p. Login to comment
68 [66G>A;859-9T>C] p.Q2220* CF 1.30 n/a n/a P 11.1 M 15.0 Asian p.R408* c.5935del 1.10 1.30 n/a n/a P 12.1&#a7; M 15.1 White p.L2027F p.R2077W 0.80 0.80 728 697 P 13.1&#a7; F 23.8 White p.R1161S 0.60 0.40 571 647 P 14.1&#a7; F 27.3 White p.P1380L p.P1380L 1.30 1.00 n/a 577 P 15.1 M 17.0 White p.G1961E c.3050&#fe;5G>A 0.88 0.88 n/a n/a P 15.2 F 22.0 White p.G1961E c.3050&#fe;5G>A 0.88 0.88 n/a n/a P 16.1 F 19.1 Black p.V989A c.4253&#fe;5G>T 0.30 0.40 97 n/a P 17.1 F 21.8 Hispanic p.A1038V p.G1441D 0.70 0.88 551 528 P 18.1 M 22.0 Indian c.859-9T>C c.5917del 0.88 0.88 527 n/a P 19.1&#a7; F 27.2 White p.G851D p.L2027F 0.88 0.88 448 459 P 19.2&#a7; F 29.2 White p.G851D p.L2027F 1.30 1.18 538 569 P 19.3 F 34.2 White p.G851D p.L2027F 1.00 1.30 442 n/a P 20.1 F 9.5 White c.5312&#fe;1G>A p.R2030* 0.88 0.70 998 929 P 21.1ߤ F 24.6 White p.N96D p.G1961E 0.30 0.18 513 549 P 21.2ߤ F 20.9 White p.N96D p.G1961E 0.30 0.40 397 355 P 22.1 M 8.0 White p. Login to comment
73 [A854T;A1038V] p.C2150Y 0.88 0.80 n/a 512 P 29.1&#a7; F 52.2 White p.A848D p.A1038V 1.00 1.00 n/a 459 P 30.1 F 40.3 Hispanic p.F938S p.R1300* 0.40 1.18 524 451 P 31.1 M 6.0 White p. Login to comment
111 [L541P; A1038V] in six carriers, p.P1380L in four carriers, and p.L2027F in three carriers. Login to comment
124 [L541P; A1038V], p.L2027F. Login to comment
137 [L541P; A1038V], p.P1380L, and p.L2027F mutations (and no p.G1961E mutation on the other allele).24 To determine whether similar differences in the segregation of qAF8 levels could also be observed for ABCA4 mutations in carriers and whether specific ABCA4 mutations may be associated with higher qAF8 levels, we plotted qAF values for carriers and affected patients who carried one of the four most common mutations (p.G1961E, p. Login to comment
146 [L541P, A1038V] (family 26), p. Login to comment
147 [L541P; A1038V] (family 1), and p.G1961E; p.P1380L (family 27). Login to comment
163 [L541P; A1038V], p.P1380L, and p.L2027F, are indicated in color. Login to comment
170 [L541P; A1038V] conferred a faster rate of lipofuscin accumulation, whereas accumulation in the presence of the p.G1961E and p.G851D mutations was slower. Login to comment
196 Thickness profiles acquired by segmentation of spectral-domain optical coherence tomography (SD-OCT) images of carriers of ABCA4 mutations p.G1961E, p.L541P/A1038V, p.P1380L, and p.L2027F. Login to comment
207 [L541P; A1038V] mutation may leave photoreceptor cells with a limited and latent capacity to deal with other sources of ER stress. Login to comment

[hide] Cerebral Involvement in Stargardt's Disease: A VBM... Invest Ophthalmol Vis Sci. 2015 Nov 1;56(12):7388-97. doi: 10.1167/iovs.15-16899. Gaia O, Melillo P, Sirio C, D'Alterio FM, Prinster A, Testa F, Brunetti A, Simonelli F, Quarantelli M
Cerebral Involvement in Stargardt's Disease: A VBM and TBSS Study.
Invest Ophthalmol Vis Sci. 2015 Nov 1;56(12):7388-97. doi: 10.1167/iovs.15-16899., [PMID:26574798]

Abstract [show]
PURPOSE: To assess whether and to what extent macro- and/or microstructural modifications are present in the brain of patients with selective central visual loss due to a juvenile macular degeneration, Stargardt's disease (STGD), taking advantage of the complementary information provided by voxel-based morphometry (VBM) and diffusion tensor imaging (DTI). METHODS: Eighteen patients with clinical and molecular diagnosis of STGD related to ABCA4 mutations and 23 normally sighted volunteers of comparable age and sex were enrolled. Structural T1-weighted (T1w) volumes, for brain tissue volume assessment by segmentation, and DTI, for the investigation of diffusivity parameters via a tract-based spatial statistics (TBSS) procedure, were acquired at 3 Tesla in all subjects. All patients underwent a complete ophthalmologic examination, including best-corrected visual acuity (BCVA), biomicroscopy, ophthalmoscopy, electroretinography (ERG), microperimetry, and optical coherence tomography (OCT). Correlations between imaging data and clinical measures were tested. RESULTS: Stargardt's disease patients showed a significant gray matter (GM) loss bilaterally in the occipital cortices, extending into the right precuneus, and in the fronto-orbital cortices. At TBSS, significant reductions in fractional anisotropy were detected throughout large regions in the supratentorial white matter (WM), more pronounced in the posterior areas. Gray matter volume correlated directly with mean visual sensitivity in the right middle frontal and left calcarine gyri, and inversely with retinal thickness in the left supramarginal gyrus. CONCLUSIONS: In STGD, widespread microstructural WM alterations are present, suggestive of minor fiber loss coupled with GM loss, also in cortical regions not traditionally linked to visual pathways, at least partly related to the retinal damage.

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No. Sentence Comment
81 Demographic and Genetic Data of STGD Patients Age Sex ABCR Mutations Age of Onset 19 F 250insCAAA G1961E D498N 4017ins24bp 11 18 M L541P/A1038V IVS40&#fe;5g->a 14 25 M L541P/A1038V G1961E 17 15 F G1961E R2149X 13 48 M N96D IVS40&#fe;5G>A 38 29 M G1961E L1938L L1894L S1689P 25 23 F L541P/A1038V F655C 14 33 M R152Q G1961E 402ins24bp 18 21 M A60V G1961E 15 23 M G690V A1598D 11 27 M G1961E R2149X 11 51 F V615A G1961E 25 54 M N96D N1436I 28 21 M 250insCAAA P402A 13 25 F R1448K c.5018&#fe;2T>C 21 49 M 4538insC IVS40&#fe;5G>A 18 23 F G1961E c.6282&#fe;1G>C 18 46 M N96D N1436I 30 T ABLE 4. Login to comment

[hide] Next-generation sequencing of ABCA4: High frequenc... Exp Eye Res. 2015 Nov 22;145:93-99. doi: 10.1016/j.exer.2015.11.011. Sciezynska A, Ozieblo D, Ambroziak AM, Korwin M, Szulborski K, Krawczynski M, Stawinski P, Szaflik J, Szaflik JP, Ploski R, Oldak M
Next-generation sequencing of ABCA4: High frequency of complex alleles and novel mutations in patients with retinal dystrophies from Central Europe.
Exp Eye Res. 2015 Nov 22;145:93-99. doi: 10.1016/j.exer.2015.11.011., [PMID:26593885]

Abstract [show]
Variation in the ABCA4 locus has emerged as the most prevalent cause of monogenic retinal diseases. The study aimed to discover causative ABCA4 mutations in a large but not previously investigated cohort with ABCA4-related diseases originating from Central Europe and to refine the genetic relevance of all identified variants based on population evidence. Comprehensive clinical studies were performed to identify patients with Stargardt disease (STGD, n = 76) and cone-rod dystrophy (CRD, n = 16). Next-generation sequencing targeting ABCA4 was applied for a widespread screening of the gene. The results were analyzed in the context of exome data from a corresponding population (n = 594) and other large genomic databases. Our data disprove the pathogenic status of p.V552I and provide more evidence against a causal role of four further ABCA4 variants as drivers of the phenotype under a recessive paradigm. The study identifies 12 novel potentially pathogenic mutations (four of them recurrent) and a novel complex allele p.[(R152*; V2050L)]. In one third (31/92) of our cohort we detected the p.[(L541P; A1038V)] complex allele, which represents an unusually high level of genetic homogeneity for ABCA4-related diseases. Causative ABCA4 mutations account for 79% of STGD and 31% of CRD cases. A combination of p.[(L541P; A1038V)] and/or a truncating ABCA4 mutation always resulted in an early disease onset. Identification of ABCA4 retinopathies provides a specific molecular diagnosis and justifies a prompt introduction of simple precautions that may slow disease progression. The comprehensive, population-specific study expands our knowledge on the genetic landscape of retinal diseases.

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9 [(L541P; A1038V)] complex allele, which represents an unusually high level of genetic homogeneity for ABCA4-related diseases. Login to comment
12 [(L541P; A1038V)] and/or a truncating ABCA4 mutation always resulted in an early disease onset. Login to comment
74 [(L541P; A1038V)] was performed by BresloweDay test and Tarone's test implemented in the SPSS software package (SPSS Inc. Chicago, IL, USA). Login to comment
86 [(L541P; A1038V)] (see Section 3.2). Login to comment
93 Except for two patients the mutation was always accompanied by p.A1038V. Login to comment
95 [(L541P; A1038V)] complex allele is well established, co-occurrence of both changes within one haplotype has been verified for selected cases, in which family samples were available for the study. Login to comment
124 [(L541P; A1038V)] correlated with AO in the direction unexpected for a non-truncating variant (Spearman R &#bc; 0.24, p &#bc; 0.019), suggesting that the effect of p. Login to comment
125 [(L541P; A1038V)] was a strong one, more similar to truncating than the non-truncating variants. Login to comment
127 [(L541P; A1038V)] thus creating a group of "strong" mutations. Login to comment
130 [(L541P; A1038V)] is shown in Fig. 2. Login to comment
139 [(L541P; A1038V)] allele, was present in more than 33.7% (31/92) of our patients, which corresponds to at least one fourth (37/143) of all alleles with an identified mutation. Login to comment
141 [(L541P; A1038V)] allele frequency of 20.1% (37/184) in our cohort is higher than the 14% (10/70) reported in Hungarian Table 1 Frequency of common ABCA4 variant alleles identified in the study compared with control subjects of European origin. Login to comment
147 [(L541P; A1038V)] (37/184) (5/1178) p < 0.0001 c. Login to comment
158 [(L541P; A1038V)] has been so far regarded as a founder mutation of mostly German origin (Hargitai et al., 2005; Rivera et al., 2000). Login to comment
160 [(L541P; A1038V)] allele among our patients was paralleled by a relatively high frequency of p.L541P- and p.A1038V-containing alleles in the Polish population. Login to comment
161 To dissect the pathogenic potential of p.L541P and p.A1038V, both mutations were examined independently. Login to comment
163 Subsequent functional studies in transgenic frogs have demonstrated that the ABCA4 protein processing is affected by p.L541P but not by p.A1038V. Login to comment
164 A mislocalization of the p.L541P mutant in the rod inner segments and correct localization of p.A1038V to rod outer segments were detected. Login to comment
167 [(L541P; A1038V)] had a strong impact on the age of disease onset in our patients. Login to comment
170 [(L541P; A1038V)] was almost three times earlier (7.8 vs. 23.7 years) than in patients with other missense or with no detectable ABCA4 mutations (data not shown). Login to comment
193 [(L541P; A1038V)] and/or truncating mutations (standard error (SE), confidence interval (CI), number of patients (n)). Login to comment
195 [(L541P; A1038V)] and/or truncating mutations on disease age of onset (AO). Login to comment
197 [(L541P; A1038V)] and/or truncating mutations One p. Login to comment
198 [(L541P; A1038V)] and/or truncating mutations Two p. Login to comment
199 [(L541P; A1038V)] and/or truncating mutations Total no. Login to comment
210 [(L541P; A1038V)] in the German and Polish patients, and p.R1129L in the Spanish patients, the data cast considerable doubt on the pathogenic potential of p.V552I. Login to comment
214 [(L541P; A1038V)] showed a strong statistically significant difference indicating that p.V552I is either non-pathogenic or has a very low penetrance. Login to comment