ABCMdb

ABCA4 p.Ala1773Val

Predicted by SNAP2:	C: N (72%), D: N (61%), E: N (72%), F: D (59%), G: N (82%), H: N (72%), I: N (66%), K: N (72%), L: N (57%), M: N (66%), N: N (78%), P: N (66%), Q: N (78%), R: N (66%), S: N (87%), T: N (87%), V: N (66%), W: D (75%), Y: N (57%),
Predicted by PROVEAN:	C: N, D: N, E: N, F: D, G: N, H: D, I: D, K: N, L: D, M: D, N: N, P: D, Q: N, R: N, S: N, T: N, V: D, W: D, Y: D,

[switch to compact view]
Comments [show]

None has been submitted yet.

Publications
[hide] ABCA4 mutational spectrum in Mexican patients with... Exp Eye Res. 2013 Apr;109:77-82. doi: 10.1016/j.exer.2013.02.006. Epub 2013 Feb 16. Chacon-Camacho OF, Granillo-Alvarez M, Ayala-Ramirez R, Zenteno JC
ABCA4 mutational spectrum in Mexican patients with Stargardt disease: Identification of 12 novel mutations and evidence of a founder effect for the common p.A1773V mutation.
Exp Eye Res. 2013 Apr;109:77-82. doi: 10.1016/j.exer.2013.02.006. Epub 2013 Feb 16., [PMID:23419329]

Abstract [show]
The aim of this study was to assess the mutational spectrum of the ABCA4 gene in a cohort of patients with Stargardt disease from Mexico, a previously uncharacterized population. Clinical diagnosis in each patient was supported by a complete ophthalmological assessment that included visual acuity measurement, a slit lamp examination, a fundus examination and photography, electroretinography, fluorescein angiography, and computerized visual fields testing. Molecular analysis was performed by PCR amplification and direct nucleotide sequence of the 50 exons of the ABCA4 gene in genomic DNA. A total of 31 unrelated subjects with the disease were enrolled in the study. Molecular analysis in the total group of 62 alleles allowed the identification of 46 mutant ABCA4 alleles carrying 29 different pathogenic disease-associated mutations. Two ABCA4 mutant alleles were detected in 20 of the 31 patients (64.5%), a single disease allele was identified in six (19.4%), and no mutant alleles were detected in five of the cases (16.1%). Most patients with two ABCA4 mutations (11/20, 55%) were compound heterozygotes. Twelve variants were novel ABCA4 mutations. Nucleotide substitutions were the most frequent type of variation, occurring in 26 out of 29 (89.7%) different mutations. The two most common mutations in our study were the missense changes p.A1773V and p.G818E, which were identified in eight (17%) and seven (15%) of the total 46 disease-associated alleles, respectively. Haplotype analyses of intragenic SNPs in four subjects carrying the p.A1773V mutation supported a common origin for this mutation. In conclusion, this is the first report of ABCA4 molecular screening in Latin American Stargardt disease patients. Our results expand the mutational spectrum of the disease by adding 12 novel ABCA4 pathogenic variants and support the occurrence of a founder effect for the p.A1773V mutation in the Mexican population. The identification of recurrent mutations in our cohort will direct future ABCA4 molecular screening in patients from this ethnic group.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
0 ABCA4 mutational spectrum in Mexican patients with Stargardt disease: Identification of 12 novel mutations and evidence of a founder effect for the common p.A1773V mutation Oscar F. Chac&#f3;n-Camacho a , Mariella Granillo-Alvarez b , Raul Ayala-Ram&#ed;rez a , Juan C. Zenteno a,c,* a Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico b Gynecology and Obstetrics Service, Hospital General de Zona No. Login to comment
10 The two most common mutations in our study were the missense changes p.A1773V and p.G818E, which were identified in eight (17%) and seven (15%) of the total 46 disease-associated alleles, respectively. Login to comment
11 Haplotype analyses of intragenic SNPs in four subjects carrying the p.A1773V mutation supported a common origin for this mutation. Login to comment
12 In conclusion, this is the first report of ABCA4 molecular screening in Latin American Stargardt disease patients. Our results expand the mutational spectrum of the disease by adding 12 novel ABCA4 pathogenic variants and support the occurrence of a founder effect for the p.A1773V mutation in the Mexican population. Login to comment
79 The two most common mutations in our study were the missense changes p.A1773V and p.G818E, which were identified in eight (17%) and seven (15%) of the total 46 disease-associated alleles, respectively (Table 2 and Supplementary Fig. 4). Login to comment
80 The most commonly mutated exon was number 38, as 12 out of 46 pathogenic alleles (26%) carried mutations in that segment, including eight alleles that harbored the recurrent p.A1773V change, two that carried the p. I1775N substitution, and two that carried the p.Y1779H replacement (Table 2). Login to comment
82 These mutations were p.R24W, p.G818E, p.P1380L, p.V1682_V1686del, p.R1705Q, p.A1773V, p.I1775N, p.Y1779H, and p.N1868I. Login to comment
84 Remarkably, the p.A1773V mutation was observed in four patients originating from the same geographical area, suggesting a founder effect. Login to comment
85 Analysis of intragenic SNPs haplotypes linked to the ABCA4 p.A1773V substitution in DNA from these subjects showed concordance for a same haplotype of SNPs rs4847281, rs3112831, rs4147831, rs 1801666, rs 1801574, and c.6543C>T (novel SNP), supporting a founder effect for this particular mutation in our population (Table 3). Login to comment
86 The haplotype linked to the p.A1773V mutationwas observed only in 2 of the 27 (7%) remaining STGD patients in this cohort. Login to comment
100 Allele 1 Allele 2 Genotype Exon Nucleotide change Polypeptide change Exon Nucleotide change Polypeptide change Familial case # 1 38 c.5318C>T p.A1773V (D) 38 c.5318C>T p.A1773V (D) Homozygous 2 e NI e e NI e e 3 6 c.634C>T p.R212C (D) 38 c.5318C>T p.A1773V (D) Compound heterozygous 4 23 c.3386G>T p.R1129L (D) 28 c.4139C>T p.P1380L (D) Compound heterozygous 5 e NI e e NI e e 6 38 c.5318C>T p.A1773V (D) 38 c.5318C>T p.A1773V (D) Homozygous 7 e NI e e NI e e 8 16 c.2453G>A p.G818E (D) 28 c.4249_4251 delTTC p.F1417del (D; N) Compound heterozygous 9 38 c.5318C>T p.A1773V (D) 38 c.5318C>T p.A1773V (D) Homozygous Sporadic case # 1 8 c.868C>T p.R290W (D) e IVS8&#fe;1G>A Splicing (D; N) Compound heterozygous 2 38 c.5318C>T p.A1773V (D) - NI - Heterozygous 3 20 c.3041T>G p.L1014R (D) 1; 49 c.52C>T; c.6764G>T p.R18W (D); p.S2255I (B) Compound heterozygous 4 13; 19 c.1804C>T; c.2828G>A p.R602W (D); p.R943Q (U) 16 c.2453G>A p.G818E (D) Compound heterozygous 5 38 c.5324T>A p. I1775N (D; N) 38 c.5324T>A p.I1775N (D; N) Homozygous 6 e NI e e NI e e 7 49 c.6764G>T p.S2255I (B) 49 c.6764 G>T p.S2255I (B) Homozygous 8 19; 40 c.2828 G>A; c.5503A>T p.R943Q (U); p.N1868I (U) 3 c.265G>T p.E89* (D; N) Compound heterozygous 9 38 c.5335T>C p.Y1779H (D;N) 38 c.5335T>C p.Y1779H (D;N) Homozygous 10 16 c.2453G>A p.G818E (D) 16 c.2453G>A p.G818E (D) Homozygous 11 6 c.723A>T p.E241D (D;N) 36 c.5114G>A p.R1705Q (D) Compound heterozygous 12 2 c.71G>A (D) p.R24H e NI e Heterozygous 13 30 c.4537_4538insC p.Q1513Pfs*41 (D; N) e NI e Heterozygous 14 32 c.4667G>C p.R1556T (D; N) 32 c.4667G>C p.R1556T (D; N) Homozygous 15 45 c.6221G>T p.G2074V (D; N) 16 c.2453G>A p.G818E (D) Compound heterozygous 16 16; 41 c.2453G>A; c.5824G>C p. G818E (D); p. E1942Q (B;N) 46 c.6384A>G p.H2128R (D) Compound heterozygous 17 16 c.2453G>A p. G818E (D) e NI e Heterozygous 18 32 c.4653G>A p. W1551* (D; N) e NI e Heterozygous 19 23 c.3386G>T p. R1129L (D) e NI e Heterozygous 20 36 c.5045_5059del GTTGCCATCTGCGTG p.V1682_ V1686del (D; N) 29; 49 c.4328G>A; c.6764G>T p.R1443H (D); p.S2255I (B) Compound heterozygous 21 19 c.2894A>G p.N965S (D) 19 c.2894A>G p.N965S (D) Homozygous 22 e NI e e NI e e STGD accounts for approximately 7% of all retinal dystrophies; it is one of the most common genetic forms of juvenile or early adult onset macular degeneration. Login to comment
108 Prior to the present study, ABCA4 molecular analysis had not been performed in Latin American STGD patients. Our results expand the disease mutational spectrum by reporting 12 novel ABCA4 mutations, and they also suggest a possible founder effect for the recurrent p.A1773V mutation. Login to comment
110 Despite the use of a variety of mutation detection techniques such as SSCP (single-strand conformation polymorphism), heteroduplex analysis, high resolution melting, and ABCA4 microarray, which in conjunction or in different combinations detect approximately 65e 75% of disease-associated alleles (Jaakson et al., 2003; Zernant et al., 2011), direct Sanger sequencing is currently considered the Table 3 Intragenic SNPs haplotype analysis in four patients carrying the ABCA4 p.A1773V mutation. Login to comment
119 ABCA4 Exon # Nucleotide change Predicted protein effect Number of alleles Population genotypic frequency in EVS Population allelic frequency in EVS (%) 1 c.52C>T p.R18W 1 TT &#bc; 0/TC &#bc; 2/CC &#bc; 6501 T &#bc; 0.015/C &#bc; 99.985 2 c.71G>A p.R24H 1 AA &#bc; 0/AG &#bc; 1/GG &#bc; 6502 A &#bc; 0.008/G &#bc; 99.992 3 c.265G>T p.E89* (N) 1 NR NR 6 c.634C>T p.R212C 1 TT &#bc; 0/TC &#bc; 2/CC &#bc; 6501 T &#bc; 0.015/C &#bc; 99.985 6 c.723A>T p.E241D (N) 1 NR NR 8 c.868C>T p.R290W 1 NR NR IVS8 IVS8 &#fe; 1G>A Splicing mutation (N) 1 NR NR 13 c.1804C>T p.R602W 1 NR NR 16 c.2453G>A p.G818E 7 NR NR 19 c.2828G>A p.R943Q 2 AA &#bc; 8/AG &#bc; 400/GG &#bc; 6095 A &#bc; 3.199/G &#bc; 96.801 19 c.2894A>G p.N965S 2 GG &#bc; 0/GA &#bc; 1/AA &#bc; 6502 G &#bc; 0.008/A &#bc; 99.992 20 c.3041T>G p.L1014R 1 NR NR 23 c.3386G>T p.R1129L 2 NR NR 28 c.4139C>T p.P1380L 1 TT &#bc; 0/TC &#bc; 2/CC &#bc; 6501 T &#bc; 0.015/C &#bc; 99.985 28 c.4249_4251del TTC p.F1417del (N) 1 NR NR 29 c.4328G>A p.R1443H 1 AA &#bc; 0/AG &#bc; 1/GG &#bc; 6502 A &#bc; 0.008/G &#bc; 99.992 30 c.4537_4538insC p.Q1513Pfs*41 (N) 1 NR NR 32 c.4653G>A p.W1551* (N) 1 NR NR 32 c.4667G>C p.R1556T (N) 2 NR NR 36 c.5044_5058del GTTGCCATCTGCGTG p.V1682_V1686del (N) 1 NR NR 36 c.5114G>A p.R1705Q 1 AA &#bc; 0/AG &#bc; 1/GG &#bc; 6502 A &#bc; 0.008/G &#bc; 99.992 38 c.5318C>T p.A1773V 8 NR NR 38 c.5324T>A p.I1775N (N) 2 NR NR 38 c.5335T>C p.Y1779H (N) 2 NR NR 40 c.5503A>T p.N1868I 1 TT &#bc; 16/TA &#bc; 589/AA &#bc; 5898 T &#bc; 4.775/A &#bc; 95.225 41 c.5824G>C p.E1942Q (N) 1 NR NR 45 c.6221G>T p.G2074V (N) 1 NR NR 46 c.6384A>G p.H2128R 1 NR NR 49 c.6764G>T p.S2255I 4 TT &#bc; 516/TG &#bc; 1473/GG &#bc; 4514 T &#bc; 19.26/G &#bc; 80.74 gold standard for ABCA4 mutational screening. Login to comment
127 The most common ABCA4 mutation in our study was c.5318C>T, located in exon 38 and predicting a p.A1773V missense change. Login to comment
130 Haplotype analyses of SNPs linked to the p.A1773V mutation were concordant in DNA from all four subjects, supporting the idea that this mutation has a common origin. Login to comment
131 To the best of our knowledge, the p.A1773V mutation has been identified in only three ABCA4 alleles from STGD patients (Stenirri et al., 2008; Burke et al., 2010) and in our study it was absent in a panel of 250 control alleles screened either by PCR-RFLP (100 alleles) or direct sequencing (150 alleles). Login to comment
135 Exon 38 was the exon most frequently mutated in our study: 12 out of 46 (26%) alleles, including eight p.A1773V, two p.I1775N, and two p.Y1779H alleles, were encoded by this segment. Login to comment
148 Furthermore, our findings support the occurrence of a founder effect for the p.A1773V mutation in the Mexican population. Login to comment

[hide] Distinct characteristics of inferonasal fundus aut... Invest Ophthalmol Vis Sci. 2013 Oct 17;54(10):6820-6. doi: 10.1167/iovs.13-12895. Duncker T, Lee W, Tsang SH, Greenberg JP, Zernant J, Allikmets R, Sparrow JR
Distinct characteristics of inferonasal fundus autofluorescence patterns in stargardt disease and retinitis pigmentosa.
Invest Ophthalmol Vis Sci. 2013 Oct 17;54(10):6820-6. doi: 10.1167/iovs.13-12895., [PMID:24071957]

Abstract [show]
PURPOSE: To report distinct characteristics of fundus autofluorescence (AF) patterns inferior to the optic disc in recessive Stargardt disease (STGD1) and retinitis pigmentosa (RP). METHODS: Short-wavelength (SW) and near-infrared (NIR) AF images were acquired from patients with STGD1 and RP. In SW- and NIR-AF images of STGD1 patients, gray levels (GL) on both sides of the demarcation line were measured. RESULTS: In STGD1, a demarcation line, which has been assigned to the closed optic fissure, was visible on SW-AF and NIR-AF inferior to the optic disc. In healthy subjects, this demarcation line is only visible by SW-AF. At 20 degrees inferior to the disc center, AF levels on the nasal side were 25% (+/-11%) lower than on the temporal side in SW-AF images and 18% (+/-11%) lower in NIR-AF images. For both STGD1 and RP, the inferonasal quadrant exhibited distinct SW- and NIR-AF patterns compared with other fundus areas. Disease-related AF changes, such as flecks, appeared to respect the demarcation line as a boundary. CONCLUSIONS: Disease-related AF patterns originating in RPE in STGD1 and RP appear to respect the demarcation line in the inferonasal quadrant of the fundus as a border. The visibility of the inferonasal demarcation line by NIR-AF in STGD1 but not in healthy eyes may indicate that increased levels of RPE lipofuscin modulate the melanin-related NIR-AF signal. This feature of NIR-AF images may aid in the diagnosis of STGD1 patients.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
51 Summary of Demographic, Clinical, and Genetic Data Patient Condition ABCA4 Mutations Sex Age, y Eye Iris Color Race/Ethnicity BCVA Snellen (logMAR) P1 STGD1 p.P1380L, p.G1961E M 12 OS Blue White 20/100 (0.70) P2 STGD1 p.P1380L, p.G1961E F 17 OS Brown White 20/150 (0.88) P3 STGD1 p.Q1003X, p.G1961E M 25 OS Brown White 20/40 (0.30) P4 STGD1 p.C54Y F 48 OD Blue White 20/30 (0.20) P5 STGD1 p.R2077W F 52 OD Blue White 20/40 (0.30) P6 STGD1 p.[L541P;A1038V] M 13 OS Brown White 20/150 (0.88) P7 STGD1 p.T972N, p.L2027F F 14 OS Blue White 20/80 (0.60) P8 STGD1 c.4537_4538insC, p.V1686M M 49 OS Brown White 20/50 (0.40) P9 STGD1 p.R1108H, p.P1380L M 50 OS Blue White 20/200 (1.00) P10 STGD1 c.5714&#fe;5G>A F 34 OD Blue White 20/200 (1.00) P11 STGD1 p.Q636H, p.G1961E M 46 OD Brown Indian 20/400 (1.30) P12 STGD1 c.5461-10T>C M 35 OD Brown Black 20/400 (1.30) P13 STGD1 p.R1640W F 20 OD Brown Black 20/125 (0.80) P14 STGD1 p.R290W M 47 OS Brown White 20/40 (0.30) P15 STGD1 p.A1773V, p.G1961E M 18 OD Brown White 20/150 (0.88) P16 AD RP p.T17M* F 23 OD Brown Hispanic 20/30 (0.20) P17 AD RP N/A M 39 OS Brown White 20/20 (0.00) P18 AR RP N/A M 50 OS Green White 20/20 (0.00) AD, autosomal dominant; AR, autosomal recessive; BCVA, best corrected visual acuity; F, female; logMAR, logarithm of the minimum angle of resolution; M, male; N/A, not available. Login to comment

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

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

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
83 [L541P; A1038V] 398 2.4 21 F 45 31 0.88 0.88 I I p.R1640W 647 613 2.6 2.8 22 M 43 7 1.00 0.00 - III p.A1773V; p.G1591G 640 6.9 23 F 41 1 0.10 CF II II p.P1486L; p.A1598D 613 572 6.0 6.5 24 F 19 4 0.60 0.70 I - p.G1961E; p.P1380L 368 2.4 25 F 23 4 0.88 0.80 - I p. Login to comment

[hide] Molecular diagnosis of putative Stargardt disease ... PLoS One. 2014 Apr 24;9(4):e95528. doi: 10.1371/journal.pone.0095528. eCollection 2014. Zhang X, Ge X, Shi W, Huang P, Min Q, Li M, Yu X, Wu Y, Zhao G, Tong Y, Jin ZB, Qu J, Gu F
Molecular diagnosis of putative Stargardt disease by capture next generation sequencing.
PLoS One. 2014 Apr 24;9(4):e95528. doi: 10.1371/journal.pone.0095528. eCollection 2014., [PMID:24763286]

Abstract [show]
Stargardt Disease (STGD) is the commonest genetic form of juvenile or early adult onset macular degeneration, which is a genetically heterogeneous disease. Molecular diagnosis of STGD remains a challenge in a significant proportion of cases. To address this, seven patients from five putative STGD families were recruited. We performed capture next generation sequencing (CNGS) of the probands and searched for potentially disease-causing genetic variants in previously identified retinal or macular dystrophy genes. Seven disease-causing mutations in ABCA4 and two in PROM1 were identified by CNGS, which provides a confident genetic diagnosis in these five families. We also provided a genetic basis to explain the differences among putative STGD due to various mutations in different genes. Meanwhile, we show for the first time that compound heterozygous mutations in PROM1 gene could cause cone-rod dystrophy. Our findings support the enormous potential of CNGS in putative STGD molecular diagnosis.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
130 Among these four reported mutations, p.A1773V in ABCA4 was reported as one of the founder mutations (up to17%) in Latin American population [18]; p.R2038W mutation in USA, Estonia and South African population; p.R602W mutation in USA, South African population [2,3,19]; G607R in the German population[20]. Login to comment
131 Taken together, this study confirmed that these four mutations are pathogenic mutations and among these four reported mutations, p.A1773V, p.R2038W and p.R602W may have higher allele frequencies since they were frequently reported in different populations. Login to comment

[hide] The external limiting membrane in early-onset Star... Invest Ophthalmol Vis Sci. 2014 Aug 19;55(10):6139-49. doi: 10.1167/iovs.14-15126. Lee W, Noupuu K, Oll M, Duncker T, Burke T, Zernant J, Bearelly S, Tsang SH, Sparrow JR, Allikmets R
The external limiting membrane in early-onset Stargardt disease.
Invest Ophthalmol Vis Sci. 2014 Aug 19;55(10):6139-49. doi: 10.1167/iovs.14-15126., [PMID:25139735]

Abstract [show]
PURPOSE: To describe pathologic changes of the external limiting membrane (ELM) in young patients with early-onset Stargardt (STGD1) disease. METHODS: Twenty-six STGD1 patients aged younger than 20 years with confirmed disease-causing adenosine triphosphate-binding cassette, subfamily A, member 4 (ABCA4) alleles and 30 age-matched unaffected individuals were studied. Spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (AF), and color fundus photography (CFP) images, as well as full-field electroretinograms were obtained and analyzed for one to four visits in each patient. RESULTS: The ELM in all patients exhibited a distinct thickening that was not observed in unaffected individuals. In addition, accumulations of reflective deposits were noted in the outer nuclear layer in every patient. Four patients exhibited a concave protuberance or bulging of a thickened and hyperreflective ELM band within the fovea containing preserved photoreceptors. Longitudinal SD-OCT data in several patients revealed the persistence of this ELM abnormality over a period of time (1-4 years). Furthermore, the edges of the inner segment ellipsoid band appeared to recede earlier than the ELM band in active lesions. CONCLUSIONS: Structural changes seen in the ELM of this cohort may reflect a gliotic response to cellular stress at the photoreceptor level in early-onset STGD1.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
93 [W1408R;R1640W] P20 18 African American 20/125 (0.80) 20/50 (0.40) 2 2 Mid 5 p.R1640W ND P21 12 Caucasian 20/50 (0.40) 20/50 (0.40) 1 1 6 p.W821R p.C2150Y P22 17 Indian 20/40 (0.30) 20/100 (0.70) 1 n/a Mid 3 p.G1961E c.6729&#fe;4_&#fe;18del P23 10 Indian 20/400 (1.30) 20/400 (1.30) 2 2 Early 3 c.885delC p.R537C P24 19 Caucasian 20/20 (0.00) 20/20 (0.00) 1 n/a ND p.G863A c.5898&#fe;1G>A P25 16 Middle Eastern 20/80 (0.60) 20/100 (0.70) 1 1 4 p.A1773V p.G1961E P26 17 Caucasian 20/150 (0.88) 20/200 (1.00) 1 1 2 p.K1547* p.R2030Q ND, not determined; n/a, not available. Login to comment

[hide] Quantitative fundus autofluorescence distinguishes... Ophthalmology. 2015 Feb;122(2):345-55. doi: 10.1016/j.ophtha.2014.08.017. Epub 2014 Oct 3. Duncker T, Tsang SH, Lee W, Zernant J, Allikmets R, Delori FC, Sparrow JR
Quantitative fundus autofluorescence distinguishes ABCA4-associated and non-ABCA4-associated bull's-eye maculopathy.
Ophthalmology. 2015 Feb;122(2):345-55. doi: 10.1016/j.ophtha.2014.08.017. Epub 2014 Oct 3., [PMID:25283059]

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

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
65 Sex Age (yrs) Race or Ethnicity Best-Corrected Visual Acuity (Logarithm of the Minimum Angle of Resolution Units) Genetic Data Average of Quantitative Fundus Autofluorescence Values of the 8 Segments ABCA4 Mutations Right Eye Left Eye Allele 1 Allele 2 Right Eye Left Eye 1 M 36 White 0.70 0.70 p.G1961E p.G1961E 282 279 2 F 46 White 0.40 0.40y p.G1961E p.R1129C 391 3 M 17 Asian Indian 0.70 0.88 p.G1961E c.6729&#fe;4_&#fe;18del 340 363 4 M 17 White 0.88 0.88 p.G1961E p.A1773V 340 366 5 M 21 White 0.88 0.88 p.G1961E p.W15* 341 325 6 F 22 White 0.70 0.48 p.G1961E p.G863A 361 351 7 F 20 White 0.70z 0.88z p.G1961E p.L541P 317 8 M 12 White 0.80 0.70 p.G1961E p.P1380L 251 242 9 F 21 White 0.88 0.88 p.G1961E p.R212C 407 439 10 F 26 White 0.40z 0.70z p.G1961E c.5196&#fe;1056A/G 379 344 11 F 24 White 0.88z 0.88z p.G1961E p.C2150R 405 396 12 F 24 White 0.30z 0.18z p.G1961E p.N96D 513 549 13 F 20 White 0.30 0.40 p.G1961E p.N96D 397 355 14 M 25 White 0.00y 0.30 p.G1961E p.Q1003* 322 328 15 M 8.2 White 0.88 0.88 p. Login to comment

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

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

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
91 [L541P;A1038V] 5 14 22.4 F White Brown 0.8 0.8 p.R212C 3 15 20.2 M White Brown 0.9 0.9 p.G1961E p.P1380L 1 16 27.6 M Arabic Brown 0.0 0.0 p.R1300* p.R2106C 3 17 26.8 M White Blue 0.5 0.5 p.G1961E c.3050&#fe;5G>A 1 18 24.9 F White Hazel 0.9 0.9 p.G1961E p.C2150R 5 19 13.2 M White Blue 0.9 1.0 p.W821R p.C2150Y 3 20 61.0 F White Green 2.0 0.0 c.250_251insCAAA 2 21 36.3 F White Blue 1.3 0.1 p.N1799D 1 22 14.1 F White Green 1.0 0.9 p.R1108C p.Q1412* 2 23 18.6 M White Brown 0.9 0.9 p.G1961E p.A1773V 3 24 53.3 F White Blue 0.3 (0.2) p.R2077W 2 BCVA values in parenthesis indicate fellow eyes that were not included in the study. Login to comment

[hide] Near-infrared autofluorescence: its relationship t... Invest Ophthalmol Vis Sci. 2015 May;56(5):3226-34. doi: 10.1167/iovs.14-16050. Greenstein VC, Schuman AD, Lee W, Duncker T, Zernant J, Allikmets R, Hood DC, Sparrow JR
Near-infrared autofluorescence: its relationship to short-wavelength autofluorescence and optical coherence tomography in recessive stargardt disease.
Invest Ophthalmol Vis Sci. 2015 May;56(5):3226-34. doi: 10.1167/iovs.14-16050., [PMID:26024107]

Abstract [show]
PURPOSE: We compared hypoautofluorescent (hypoAF) areas detected with near-infrared (NIR-AF) and short-wavelength autofluorescence (SW-AF) in patients with recessive Stargardt disease (STGD1) to retinal structure using spectral domain optical coherence tomography (SD-OCT). METHODS: The SD-OCT volume scans, and SW-AF and NIR-AF images were obtained from 15 eyes of 15 patients with STGD1 and registered to each other. Thickness maps of the total retina, receptor-plus layer (R+, from distal border of the RPE to outer plexiform/inner nuclear layer boundary), and outer segment-plus layer (OS+, from distal border of the RPE to ellipsoid zone [EZ] band) were created from SD-OCT scans. These were compared qualitatively and quantitatively to the hypoAF areas in SW-AF and NIR-AF images. RESULTS: All eyes showed a hypoAF area in the central macula and loss of the EZ band in SD-OCT scans. The hypoAF area was larger in NIR than SW-AF images and it exceeded the area of EZ band loss for 12 eyes. The thickness maps showed progressive thinning towards the central macula, with the OS+ layer showing the most extensive and severe thinning. The central hypoAF areas on NIR corresponded to the OS+ thinned areas, while the hypoAF areas on SW-AF corresponded to the R+ thinned areas. CONCLUSIONS: Since the larger hypoAF area on NIR-AF exceeded the region of EZ band loss, and corresponded to the OS+ thinned area, RPE cell loss occurred before photoreceptor cell loss. The NIR-AF imaging may be an effective tool for following progression and predicting loss of photoreceptors in STGD1.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
74 Selected Demographic, Clinical, and Genetic Characteristics of the Study Cohort Patient Sex Disease-Associated ABCA4 Variant(s) Age Eye BCVA 1 F p.G1961E; c2382&#fe;1G>A 36 OS 0.8 2 M p.[L541P;A1038V] 8 OS 0.6 3 M p.G1961E; c.6729&#fe;5_&#fe;19del 18 OS 0.9 4 M p.P1380L; p.G1961E 12 OD 0.8 5 M c.571-1G>T 43 OD 0.4 6 M p.Q1003*; p.G1961E 25 OS 0 7 M p.[L541P;A1038V]; p.L2027F 8 OD N/A 8 F p.R212C; p.G1961E 22 OD 0.8 9 F p.P1380L; p.G1961E 20 OD 0.9 10 M p.R1300*; p.R2106C 26 OS 0 11 M c.3050&#fe;5G>A; p.G1961E 27 OD 0.5 12 F p.G1961E; p.C2150R 25 OD 0.7 13 M p.W821R; p.C2150Y 13 OD 0.4 14 F p.N1799D 36 OD 1.3 15 M p.A1773V; p.G1961E 19 OD 0.7 FIGURE 1. Login to comment

[hide] Next-generation sequencing applied to a large Fren... Orphanet J Rare Dis. 2015 Jun 24;10:85. doi: 10.1186/s13023-015-0300-3. Boulanger-Scemama E, El Shamieh S, Demontant V, Condroyer C, Antonio A, Michiels C, Boyard F, Saraiva JP, Letexier M, Souied E, Mohand-Said S, Sahel JA, Zeitz C, Audo I
Next-generation sequencing applied to a large French cone and cone-rod dystrophy cohort: mutation spectrum and new genotype-phenotype correlation.
Orphanet J Rare Dis. 2015 Jun 24;10:85. doi: 10.1186/s13023-015-0300-3., [PMID:26103963]

Abstract [show]
BACKGROUND: Cone and cone-rod dystrophies are clinically and genetically heterogeneous inherited retinal disorders with predominant cone impairment. They should be distinguished from the more common group of rod-cone dystrophies (retinitis pigmentosa) due to their more severe visual prognosis with early central vision loss. The purpose of our study was to document mutation spectrum of a large French cohort of cone and cone-rod dystrophies. METHODS: We applied Next-Generation Sequencing targeting a panel of 123 genes implicated in retinal diseases to 96 patients. A systematic filtering approach was used to identify likely disease causing variants, subsequently confirmed by Sanger sequencing and co-segregation analysis when possible. RESULTS: Overall, the likely causative mutations were detected in 62.1 % of cases, revealing 33 known and 35 novel mutations. This rate was higher for autosomal dominant (100 %) than autosomal recessive cases (53.8 %). Mutations in ABCA4 and GUCY2D were responsible for 19.2 % and 29.4 % of resolved cases with recessive and dominant inheritance, respectively. Furthermore, unexpected genotype-phenotype correlations were identified, confirming the complexity of inherited retinal disorders with phenotypic overlap between cone-rod dystrophies and other retinal diseases. CONCLUSIONS: In summary, this time-efficient approach allowed mutation detection in the most important cohort of cone-rod dystrophies investigated so far covering the largest number of genes. Association of known gene defects with novel phenotypes and mode of inheritance were established.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
100 Np Highly - - - Novel CIC05853 simplex + ABC4A NM_000350.2 Ho 22 c.3259G>A p.E1087K Np Highly Prd D Dc (Allikmets et al. 1997) (rs61751398) [81] CIC05854 Ar + ABC4A NM_000350.2 Ho 35 c.4919G>A p.(R1640Q) + Highly Prd D Dc (Simonelli et al. 2000) (rs61751403) [82] CIC05989 simplex ABC4A NM_000350.2 Het 34 c.4837G>A p.(D1613N) + Not B D Dc Novel ABC4A NM_000350.2 Het 10 c.1302del p.(Q437Rfs*12) + - - - - Novel ABCA4 NM_000350.2 Het 38 c.5318C>T p.(A1773V) + Moderately Prd D Dc (Stenirri et al. 2008) [83] CIC06170 simplex ABC4A NM_000350.2 Het 44 c.6089G>A p.(R2030Q) + Highly Prd D Dc (Lewis et al. 1999) (rs61750641) ABC4A NM_000350.2 Het IVS 24 c.3607+3A>T r.(spl?) Login to comment

[hide] Identification of Genetic Defects in 33 Probands w... PLoS One. 2015 Jul 10;10(7):e0132635. doi: 10.1371/journal.pone.0132635. eCollection 2015. Xin W, Xiao X, Li S, Jia X, Guo X, Zhang Q
Identification of Genetic Defects in 33 Probands with Stargardt Disease by WES-Based Bioinformatics Gene Panel Analysis.
PLoS One. 2015 Jul 10;10(7):e0132635. doi: 10.1371/journal.pone.0132635. eCollection 2015., [PMID:26161775]

Abstract [show]
Stargardt disease (STGD) is the most common hereditary macular degeneration in juveniles, with loss of central vision occurring in the first or second decade of life. The aim of this study is to identify the genetic defects in 33 probands with Stargardt disease. Clinical data and genomic DNA were collected from 33 probands from unrelated families with STGD. Variants in coding genes were initially screened by whole exome sequencing. Candidate variants were selected from all known genes associated with hereditary retinal dystrophy and then confirmed by Sanger sequencing. Putative pathogenic variants were further validated in available family members and controls. Potential pathogenic mutations were identified in 19 of the 33 probands (57.6%). These mutations were all present in ABCA4, but not in the other four STGD-associated genes or in genes responsible for other retinal dystrophies. Of the 19 probands, ABCA4 mutations were homozygous in one proband and compound heterozygous in 18 probands, involving 28 variants (13 novel and 15 known). Analysis of normal controls and available family members in 12 of the 19 families further support the pathogenicity of these variants. Clinical manifestation of all probands met the diagnostic criteria of STGD. This study provides an overview of a genetic basis for STGD in Chinese patients. Mutations in ABCA4 are the most common cause of STGD in this cohort. Genetic defects in approximately 42.4% of STGD patients await identification in future studies.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
158 Chacon-Camacho OF, Granillo-Alvarez M, Ayala-Ramirez R, Zenteno JC. ABCA4 mutational spectrum in Mexican patients with Stargardt disease: Identification of 12 novel mutations and evidence of a founder effect for the common p.A1773V mutation. Login to comment

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

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

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
75 [W1408R;R1640W] 1.00 1.00 n/a n/a P 33.1&#a7; M 23.0 White p.R2030Q p.G1961E 1.00 1.00 334 347 P 34.1 M 46.9 White p.C1490Y p.G1961E 0.40 0.30 376 384 P 35.1ߥ M 24.8 White c.3050&#fe;5G>A p.G1961E 0.00 0.00 381 451 P 36.1ߥ F 29.3 Hispanic p.L541P p.G1961E 0.40 0.40 479 487 P 37.1ߤ F 24.7 White p.G1961E p.C2150R 0.88 0.88 405 396 P 38.1&#a7; M 11.7 White p.W821R p.C2150Y 0.40 0.40 306 n/a P 39.1 F 12.8 White p.P1380L c.5714&#fe;5G>A 0.60 0.40 558 573 P 39.2 M 14.1 White p.P1380L c.5714&#fe;5G>A 0.88 0.88 395 462 P 40.1ߤ F 16.2 White p.K1547* p.R2030Q 0.70 0.40 481 513 P 41.1 F 19.0 White p.C54Y 0.88 0.88 n/a n/a P 42.1ߤ F 13.0 White p.R1108C p.Q1412* 1.30 1.00 511 528 P 43.1ߤ M 17.4 White p.A1773V p.G1961E 0.88 0.88 340 366 P 44.1 M 14.0 Asian p.R408* c.4248_4250del 1.30 1.30 n/a n/a P 44.2 F 7.0 Asian p.R408* c.4248_4250del 1.30 1.30 n/a n/a P 45.1 F 42.4 White p.N965Y p.P1486L 0.10 0.40 n/a n/a BCVA, best-corrected visual acuity; logMAR, logarithm of the minimum angle of resolution; OD, right eye; OS, left eye; qAF8, average quantitative autofluorescence of the 8 measurement sites from all available images per eye; n/a, not available. Login to comment

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

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

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
32 Some of them have a high prevalence in certain ethnic groups, such as p.C1490Y in South Africans (September et al., 2004), p.A1773V in Mexicans (Chacon-Camacho et al., 2013) and a number of other mutations specific for different European populations (Rivera et al., 2000; Valverde et al., 2006; Maugeri et al., 1999; Rosenberg et al., 2007), which underlines the need of genotyping patients of various ethnicities. Login to comment