ABCMdb

ABCA4 p.Val767Asp

ClinVar:	c.2300T>A , p.Val767Asp ? , not provided
Predicted by SNAP2:	A: N (53%), C: N (53%), D: D (91%), E: D (53%), F: D (63%), G: D (71%), H: N (53%), I: N (82%), K: D (63%), L: N (72%), M: N (61%), N: D (59%), P: D (66%), Q: D (53%), R: D (63%), S: D (53%), T: N (61%), W: D (80%), Y: D (63%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: N, G: D, H: D, I: N, K: D, L: N, M: N, N: D, P: D, Q: D, R: D, S: D, T: D, W: D, Y: D,

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[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] 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
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
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

[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] Loss of peripapillary sparing in non-group I Starg... Exp Eye Res. 2010 Nov;91(5):592-600. Epub 2010 Aug 7. Burke TR, Allikmets R, Smith RT, Gouras P, Tsang SH
Loss of peripapillary sparing in non-group I Stargardt disease.
Exp Eye Res. 2010 Nov;91(5):592-600. Epub 2010 Aug 7., [PMID:20696155]

Abstract [show]
The aim of this study was to assess peripapillary sparing in patients with non-group I Stargardt disease. We suggest this as a useful clinical sign for formulating disease severity. Patients with a diagnosis of Stargardt disease were grouped by electroretinogram (ERG). Fundus autofluorescence was used to assess the peripapillary area for involvement in the Stargardt disease process. From a cohort of 32 patients (64 eyes), 17 patients (33 eyes) demonstrated loss of peripapillary sparing. One of 15 patients in Group I, six of 7 patients in group II and 9 of 10 patients in group III demonstrated peripapillary atrophy. One patient in group II had peripapillary flecks. All patients had at least one mutation detected in the ABCA4 gene. Both mutations were detected in 21 patients. Patients in groups II and III had the earliest ages of onset and the poorest visual acuities. Two novel disease causing mutation in the ABCA4 gene were detected. Our data supports the observation that peripapillary sparing is not universal finding for Stargardt disease and peripapillary atrophy is a useful clinical sign for identifying patients with Stargardt disease who fall into the more severe ERG groups, i.e. groups II and III. The presence of atrophy suggests a continuum of disease between groups II and III. Loss of peripapillary sparing is likely associated with the more deleterious mutations of the ABCA4 gene.

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184 Also, the type of involvement of the peripapillary area Table 1 Summary of clinical and genetic information for patients with ERG Group I Stargardt Disease. Case Mutation Mutation OA Duration Age at AF Visual Acuity Flecks Atrophy GA (mm2 ) PPA # Sex Allele 1 Allele 2 PPA (years) (years) (years) OD OS OD OS OD OS OD OS Pattern RON 1 Male G1961E G1961E e 19 13 32 20/70 20/70 M M M M 1.6 0.2 None 2 Female G1961E *IVS43 þ 1 G > T e 8 21 27 20/200 20/200 M M M M na na None 3.1 Male L541P/A1038V G1961E e 28 3 31 20/50 20/30 M M M M na na None 3.2 Male L541P/A1038V G1961E e 28 5 33 20/60 20/50 M M M M na na None 4.1 Female L541P/A1038V G1961E e 14 3 17 20/30 20/25 None None None None na na None 4.2 Female L541P/A1038V G1961E e 14 10 24 20/150 20/200 M M M M na na None 5 Female G1961E R2077W e 25 5 30 20/60 20/50 None None M M na na None 6.1 Female G1961E L541P/A1038V e 18 3 21 20/150 20/150 None None M M na na None 6.2 Female G1961E L541P/A1038V e 15 3 18 20/150 20/150 None None M M na na None 7 Female R602Q R602Q e 31 5 36 20/20 20/60 M,EM M,EM M M 0.7 0.3 None 8 Male L541P/A1038V ND e 22 24 46 20/200 20/200 M M M M 13.2 4.1 None 9 Femlae A1038V ND e 27 10 37 20/100 20/60 M,EM M,EM M M na na None 10 Female G1961E ND e 27 6 33 20/150 20/150 M M M M na na None 11 Female G1961E ND e 43 24 67 20/40 20/200 M M M M 4.8 na None 12 Male R212C ND OU 5 23 28 20/200 20/200 M,EM M,EM M M 1.6 4.2 Patchy N,T Abbreviations: ERG, electroretinogram; PPA, peripapillary atrophy; OD, right eye; OS, left eye; OU, both eyes; OA, onset age; AF, autofluoresence; M, macula; EM, extramacular retina; GA, geographic atrophy; na, not available; RON, relation to optic nerve; N, nasal; T, temporal; ND, mutation was not detected by the ABCR array e suggesting the presence of a currently unknown mutant allele; and *newly described mutation. Login to comment
185 Table 2 Summary of clinical and genetic information for patients with ERG Groups II or III Stargardt Disease. Case Mutation Mutation ERG OA Duration Age at AF Visual Acuity Flecks GA position GA (mm2) PPA # Sex Allele 1 Allele 2 PPA Group (years) (years) (years) OD OS OD OS OD OS OD OS Pattern RON 13 Female P1380L R1640Q OU II 11 24 35 HM HM EM EM M,EM M,EM na na Scalloped - 14 Male IVS38-10 T>C IVS40+5 G>A OU II 7 6 13 20/150 20/150 M,EM M,EM M M na na Flecks N 15 Female M1 V/R2030Q P1380L OU II 8 10 18 20/150 20/150 M,EM M,EM M M 3.52 na Patchy N,T 16 Female P1380L P1380L OU II 18 8 26 20/400 20/400 M,EM M,EM M M 0.25 na Patchy N,T 17 Female L541P/A1038 V L2027F OU II 10 22 32 CF CF M,EM M,EM M M 11.7 5.1 Patchy N,T 18 Male A1773 V ND OU II 35 6 41 CF 20/30 M,EM M,EM M M 4.2 3.7 Patchy N,T 19 Female L2027F ND OU I/II 10 17 27 20/400 20/400 M,EM M,EM M M 1.6 0.1 Patchy N,T 20 Male R602 W R1300X OU III 8 18 26 CF CF None None M,EM M,EM na na Scalloped N,T 21 Female C54Y IVS14+1 G>C OU III 8 55 63 CF HM EM None M,EM M,EM na na Complete - 22.1 Male 4537delC *R107X OU III 5 8 13 20/200 20/200 EM EM M M 2.3 1.7 Patchy N,T 22.2 Female 4537delC *R107X - III 6 2 8 20/200 20/200 M,EM M,EM M M na na - - 23 Male P1380L IVS40+5 G>A OU III 29 26 55 20/400 20/400 EM EM M,EM M,EM na na Complete - 24 Male A1598D A1598D OU III 13 40 53 20/400 20/400 NA NA M,EM M,EM na na Scalloped N,T 25 Male G172S ND OU III 25 7 32 CF CF None None M,EM M,EM na na Complete - 26 Female R1108C ND OU III 9 50 59 20/400 20/400 EM EM M,EM M,EM na na Complete - 27 Male V767D ND OD III 5 10 15 20/400 20/400 EM EM M M na na Patchy T 28 Male P1380L ND OU II/III 9 21 30 20/400 20/400 EM EM M M na na Patchy N,T Abbreviations: ERG, electroretinogram; PPA, peripapillary atrophy; OD, right eye; OS, left eye; OU, both eyes; OA, onset age; AF, autofluoresence; M, macula; EM, extramacular retina; GA, geographic atrophy; na, not available; RON, relation to optic nerve; N, nasal; T, temporal; ND, mutation was not detected by the ABCR array, suggesting the presence of a currently unknown mutant allele; and *newly described mutation. 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

[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] Spectrum of the ABCA4 gene mutations implicated in... Invest Ophthalmol Vis Sci. 2007 Mar;48(3):985-90. Valverde D, Riveiro-Alvarez R, Aguirre-Lamban J, Baiget M, Carballo M, Antinolo G, Millan JM, Garcia Sandoval B, Ayuso C
Spectrum of the ABCA4 gene mutations implicated in severe retinopathies in Spanish patients.
Invest Ophthalmol Vis Sci. 2007 Mar;48(3):985-90., [PMID:17325136]

Abstract [show]
PURPOSE: The purpose of this study is to describe the spectrum of mutations in the ABCA4 gene found in Spanish patients affected with several retinal dystrophies. METHODS: Sixty Spanish families with different retinal dystrophies were studied. Samples were analyzed for variants in all 50 exons of the ABCA4 gene by screening with the ABCR400 microarray, and results were confirmed by direct sequencing. Haplotype analyses were also performed. For those families with only one mutation detected by the microarray, denaturing (d)HPLC was performed to complete the mutational screening of the ABCA4 gene. RESULTS: The sequence analysis of the ABCA4 gene led to the identification of 33 (27.5%) potential disease-associated alleles among the 60 patients. These comprised 16 distinct sequence variants in 25 of the 60 subjects investigated. For autosomal recessive cone-rod dystrophy (arCRD), we found that 50% of the CRD families with the mutation had two recurrent changes (2888delG and R943Q). For retinitis pigmentosa (RP) and autosomal dominant macular dystrophy (adMD), one putative disease-associated allele was identified in 9 of the 27 and 3 of the 7 families, respectively. CONCLUSIONS: In the population studied, ABCA4 plays an important role in the pathogenesis of arCRD. However, mutations in this gene are less frequently identified in other retinal dystrophies, like RP or adMD, and therefore it is still not clear whether ABCA4 is involved as a modifying factor or the relationship is a fortuitous association.

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87 TABLE 3. Genetic Analyses of ABCA4 Changes in Nine Families with Autosomal Recessive RP Family Allele 1 Allele 2 Nucleotide Change Amino Acid Change Nucleotide Change Amino Acid Change SRP-716 6764G3T S2255I (likely nonpathogenic) c.858 ؉8T3G SRP-766 2300T3A V767D c.858 ؉8T3G SRP-775 466A3G I156V c.858 ؉8T3G SRP-818 6764G3T S2255I (likely nonpathogenic) SRP-834 c.5547ϩ5G3A Splice acceptor SRP-854 6764G3T S2255I B57 466A3G I156V B173 2828G3A R943Q G5466A L1821L B278 2701A3G T901A [G1961E; S2255I] did not support the pathologic role of this mutation in the family. Login to comment
85 TABLE 3. Genetic Analyses of ABCA4 Changes in Nine Families with Autosomal Recessive RP Family Allele 1 Allele 2 Nucleotide Change Amino Acid Change Nucleotide Change Amino Acid Change SRP-716 6764G3T S2255I (likely nonpathogenic) c.858 d19;8T3G SRP-766 2300T3A V767D c.858 d19;8T3G SRP-775 466A3G I156V c.858 d19;8T3G SRP-818 6764G3T S2255I (likely nonpathogenic) SRP-834 c.5547af9;5G3A Splice acceptor SRP-854 6764G3T S2255I B57 466A3G I156V B173 2828G3A R943Q G5466A L1821L B278 2701A3G T901A [G1961E; S2255I] did not support the pathologic role of this mutation in the family. 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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59 15428 Isolated 1622T4C; 3113C4T L541P; A1038V 2300T4A V767D ? 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] 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] 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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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

[hide] Null missense ABCR (ABCA4) mutations in a family w... Invest Ophthalmol Vis Sci. 2001 Nov;42(12):2757-61. Shroyer NF, Lewis RA, Yatsenko AN, Lupski JR
Null missense ABCR (ABCA4) mutations in a family with stargardt disease and retinitis pigmentosa.
Invest Ophthalmol Vis Sci. 2001 Nov;42(12):2757-61., [PMID:11687513]

Abstract [show]
PURPOSE: To determine the type of ABCR mutations that segregate in a family that manifests both Stargardt disease (STGD) and retinitis pigmentosa (RP), and the functional consequences of the underlying mutations. METHODS: Direct sequencing of all 50 exons and flanking intronic regions of ABCR was performed for the STGD- and RP-affected relatives. RNA hybridization, Western blot analysis, and azido-adenosine triphosphate (ATP) labeling was used to determine the effect of disease-associated ABCR mutations in an in vitro assay system. RESULTS: Compound heterozygous missense mutations were identified in patients with STGD and RP. STGD-affected individual AR682-03 was compound heterozygous for the mutation 2588G-->C and a complex allele, [W1408R; R1640W]. RP-affected individuals AR682-04 and-05 were compound heterozygous for the complex allele [W1408R; R1640W] and the missense mutation V767D. Functional analysis of the mutation V767D by Western blot and ATP binding revealed a severe reduction in protein expression. In vitro analysis of ABCR protein with the mutations W1408R and R1640W showed a moderate effect of these individual mutations on expression and ATP-binding; the complex allele [W1408R; R1640W] caused a severe reduction in protein expression. CONCLUSIONS: These data reveal that missense ABCR mutations may be associated with RP. Functional analysis reveals that the RP-associated missense ABCR mutations are likely to be functionally null. These studies of the complex allele W1408R; R1640W suggest a synergistic effect of the individual mutations. These data are congruent with a model in which RP is associated with homozygous null mutations and with the notion that severity of retinal disease is inversely related to residual ABCR activity.

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8 RP-affected individuals AR682-04 and-05 were compound heterozygous for the complex allele [W1408R; R1640W] and the missense mutation V767D. Login to comment
9 Functional analysis of the mutation V767D by Western blot and ATP binding revealed a severe reduction in protein expression. Login to comment
46 Oligos corresponding to each mutation were: V767D, GTC TGG CAG CAG CCT GTA GTG GTG ACA TCT ATT TCA C; W1408R, GAC CCT TCA CCC CCG GAT ATA TGG GCA G; R1640W, CAA CGC CAT CTT ATG GGC CAG CCT GCC (mutant nucleotide positions are in bold type). Login to comment
76 Sequencing of STGD1-affected proband AR682-03 revealed three ABCR mutations: the transition 4222T3C that encodes the missense substitution W1408R, the transition 4918C3T that results in the missense substitution R1640W, and the transversion 2588G3C that gives rise to equal amounts of proteins with either a deletion of glycine at residue 863 or the missense substitution G863A (Fig. 2, Table 1).10,15,16 Sequencing of her RP-affected paternal grandmother, AR682-04, also revealed three ABCR mutations: the missense substitutions W1408R and R1640W and a transversion 2300T3A that encodes the missense substitution V767D (Fig. 2, Table 1).17 Direct DNA sequencing of all members of pedigree AR682 for the exons corresponding to these mutations revealed segregation of the mutation 2588G3C from the maternal lineage and the complex allele [W1408R; R1640W] from the paternal lineage; the mutation V767D was identified only in the two RP-affected individuals (Fig. 2). Login to comment
80 Biochemical Analysis of Recombinant ABCR Plasmid constructs encoding recombinant ABCR proteins bearing the missense mutations V767D, W1408R, and R1640W, and the complex allele [W1408R; R1640W] were transiently transfected into HEK 293T cells. Login to comment
88 Western blot analysis of proteins from cells transfected with the V767D or [W1408R; R1640W] mutation-bearing constructs showed very little, if any, protein (Fig. 4). Login to comment
91 Recombinant ABCR bearing the V767D or [W1408R; R1640W] mutations showed no labeling with azido-ATP, even when fivefold total protein was used in the assay (Fig. 4 and data not shown). Login to comment
102 ABCR Alterations in Patients with Stargardt Disease and Retinitis Pigmentosa Exon Nucleotide Amino Acid AR682-03 AR682-04 3 302ϩ26 A/A A/G 10 1268G 3 A H423R A/A A/G 1356ϩ11delG 6G/6G 6G/7G 15 2300T 3 A V767D T/T T/A 17 2588G 3 C G863A G/C G/G 19 2828G 3 A R943Q G/A G/G 24 3523-30 A/T A/T 28 4203C 3 A P1401P C/A C/C 4222T 3 C W1408R C/T C/T 33 4667ϩ48 C/T T/T 35 4918C 3 T R1640W C/T C/T 40 5585-70 C/T T/T 5603A 3 T N1868I A/T A/A 5682G 3 C L1894L G/C G/G Mutations are indicated in bold. Login to comment
116 In individual AR682-03, the combination of the 2588G3C allele with the complex allele [W1408R; R1640W] resulted in STGD1 with onset of visual symptoms at age 15 years, consistent with classification of the [W1408R; R1640W] allele as moderate to severe. Login to comment
117 RP-affected individuals AR682-04 and -05 carry the complex allele [W1408R; R1640W] in trans to the missense allele V767D. Login to comment
121 ATP labeling and Western blot analysis of recombinant ABCR bearing the mutations V767D or [W1408R; R1640W] showed that these mutant proteins are not efficiently expressed in our transient transfection system, despite expression of substantial amounts of mRNA (Figs. Login to comment
123 Based on our new observations, we predict that both RP-associated alleles V767D and [W1408R; R1640W] represent severe mutations that result in little or no ABCR activity. Login to comment
125 In support of the misfolding hypothesis, the mutation V767D is predicted to lie within a transmembrane region and may disrupt proper folding of the nascent protein. Login to comment
126 However, the alterations W1408R and R1640W are each predicted to affect the first intradiscal loop, which has no known function.22 Of interest, the mutation V767D was reported in combination with the mutation 250delCAAA (a frameshift mutation that is a presumed null allele) in a patient with STGD1 with onset at age 8 years.17 That this patient (now 24 years old) has an ABCR genotype predicted to be equal to or more severe than that of our patient with advanced RP suggests a potential role for environmental or modifier gene effects. Login to comment
45 Oligos corresponding to each mutation were: V767D, GTC TGG CAG CAG CCT GTA GTG GTG ACA TCT ATT TCA C; W1408R, GAC CCT TCA CCC CCG GAT ATA TGG GCA G; R1640W, CAA CGC CAT CTT ATG GGC CAG CCT GCC (mutant nucleotide positions are in bold type). Login to comment
75 Sequencing of STGD1-affected proband AR682-03 revealed three ABCR mutations: the transition 4222T3C that encodes the missense substitution W1408R, the transition 4918C3T that results in the missense substitution R1640W, and the transversion 2588G3C that gives rise to equal amounts of proteins with either a deletion of glycine at residue 863 or the missense substitution G863A (Fig. 2, Table 1).10,15,16 Sequencing of her RP-affected paternal grandmother, AR682-04, also revealed three ABCR mutations: the missense substitutions W1408R and R1640W and a transversion 2300T3A that encodes the missense substitution V767D (Fig. 2, Table 1).17 Direct DNA sequencing of all members of pedigree AR682 for the exons corresponding to these mutations revealed segregation of the mutation 2588G3C from the maternal lineage and the complex allele [W1408R; R1640W] from the paternal lineage; the mutation V767D was identified only in the two RP-affected individuals (Fig. 2). Login to comment
79 Biochemical Analysis of Recombinant ABCR Plasmid constructs encoding recombinant ABCR proteins bearing the missense mutations V767D, W1408R, and R1640W, and the complex allele [W1408R; R1640W] were transiently transfected into HEK 293T cells. Login to comment
87 Western blot analysis of proteins from cells transfected with the V767D or [W1408R; R1640W] mutation-bearing constructs showed very little, if any, protein (Fig. 4). Login to comment
90 Recombinant ABCR bearing the V767D or [W1408R; R1640W] mutations showed no labeling with azido-ATP, even when fivefold total protein was used in the assay (Fig. 4 and data not shown). Login to comment
101 ABCR Alterations in Patients with Stargardt Disease and Retinitis Pigmentosa Exon Nucleotide Amino Acid AR682-03 AR682-04 3 302af9;26 A/A A/G 10 1268G 3 A H423R A/A A/G 1356af9;11delG 6G/6G 6G/7G 15 2300T 3 A V767D T/T T/A 17 2588G 3 C G863A G/C G/G 19 2828G 3 A R943Q G/A G/G 24 3523-30 A/T A/T 28 4203C 3 A P1401P C/A C/C 4222T 3 C W1408R C/T C/T 33 4667af9;48 C/T T/T 35 4918C 3 T R1640W C/T C/T 40 5585-70 C/T T/T 5603A 3 T N1868I A/T A/A 5682G 3 C L1894L G/C G/G Mutations are indicated in bold. Login to comment
120 ATP labeling and Western blot analysis of recombinant ABCR bearing the mutations V767D or [W1408R; R1640W] showed that these mutant proteins are not efficiently expressed in our transient transfection system, despite expression of substantial amounts of mRNA (Figs. 3, 4). Login to comment
124 However, the alterations W1408R and R1640W are each predicted to affect the first intradiscal loop, which has no known function.22 Of interest, the mutation V767D was reported in combination with the mutation 250delCAAA (a frameshift mutation that is a presumed null allele) in a patient with STGD1 with onset at age 8 years.17 That this patient (now 24 years old) has an ABCR genotype predicted to be equal to or more severe than that of our patient with advanced RP suggests a potential role for environmental or modifier gene effects. 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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No. Sentence 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] 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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Sentences [show]
No. Sentence Comment
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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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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[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
62 Five mutations were unique for this study: missense changes V767D (exon 15), T897I (exon 18), E1399K (exon 28), insertion of four nucleotides CAAA at position 250 in exon 3, and a splice site variant 5018 ϩ 2T/C in exon 36. 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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38 Fundus autofluorescence image of the left eye of patient 3032 harboring ABCA4 variants c.2300Tb0e;A (p.V767D) and c.735Tb0e;G (p.Y245*). Login to comment

[hide] Clinical and molecular genetic study of 12 Italian... Genet Mol Res. 2012 Dec 17;11(4):4342-50. doi: 10.4238/2012.October.9.3. Oldani M, Marchi S, Giani A, Cecchin S, Rigoni E, Persi A, Podavini D, Guerrini A, Nervegna A, Staurenghi G, Bertelli M
Clinical and molecular genetic study of 12 Italian families with autosomal recessive Stargardt disease.
Genet Mol Res. 2012 Dec 17;11(4):4342-50. doi: 10.4238/2012.October.9.3., [PMID:23096905]

Abstract [show]
Stargardt disease was diagnosed in 12 patients from 12 families using complete ophthalmologic examination, fundus photography, fundus autofluorescence, and spectral-domain optical coherence tomography. DNA was extracted for polymerase chain reaction (PCR) and direct DNA sequencing (ABCA4 gene). Genetic counseling and eye examination were offered to 16 additional family members. Various patterns of presentation were observed in patients with clinical diagnoses of Stargardt disease. The genetic study identified 2 mutations in 75% of families (9/12); a second mutation could not be found in the remaining 25% of families (3/12). The most frequent mutation was G1961E, found in 17% of families (2/12). This finding is similar to that of a previous analysis report of an Italian patient series. Four new mutations were also identified: Tyr1858Asp, Leu1195fsX1196, p.Tyr850Cys, and p.Thr959Ala. Our results suggest that PCR and direct DNA sequencing are the most appropriate techniques for the analysis of the ABCA4 gene. However, this method requires supplementation with specific PCR analysis to diagnose large deletions. The study of the families identified healthy carriers and affected subjects in presymptomatic stages and was also useful for evaluating the risk of transmission to progeny. Combined ophthalmologic and genetic evaluation enabled better clinical management of these families.

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69 of patients Subject Allele 1 Allele 2 Age of diagnosis (years) Visual acuity Right eye Left eye 1 F1 ID81 Tyr1858Asp Met1Val; Arg2030Gln 22 20/50 20/32 2 F2 ID220 Ile156Val Gly607Arg; Gly1961Glu 30 20/800 20/400 3 F3 ID362 Met1Val Gly1961Glu; Arg2030Gln 60 20/40 20/32 4 F4 ID197 Asp1532Asn Arg2030term 40 20/32 20/32 5 F6 ID363 Tyr362Term Gly863Ala 16 20/200 20/250 6 F7 ID365 Arg1098Cys Cys1488Arg 50 20/32 20/800 7 F8 ID394 Arg18Trp Val767Asp 10 20/800 20/800 8 F9 ID396 IVS40+5G>A IVS13+1G>A 19 20/40 20/50 9 F10 ID366 p.Gln1513Profs*42 - 20 20/200 20/200 10 F12 ID377 Leu1195Argfs*2 - 50 20/32 20/20 11 F13 ID4 Cys2150Tyr - 70 20/400 20/400 12 F17 ID457 p.Tyr850Cys p.Thr959Ala 50 20/20 20/40 F1 = family 1; ID = reference code to a specific patient. 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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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