ABCMdb

ABCA4 p.Ser2255Ile

ClinVar:	c.6764G>T , p.Ser2255Ile N , Benign/Likely benign, not provided
Predicted by SNAP2:	A: N (72%), C: N (53%), D: N (66%), E: N (72%), F: D (53%), G: N (72%), H: N (72%), I: N (61%), K: N (82%), L: N (53%), M: N (57%), N: N (53%), P: N (61%), Q: N (78%), R: N (78%), T: N (87%), V: N (61%), W: D (71%), Y: N (53%),
Predicted by PROVEAN:	A: N, C: N, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, N: N, P: N, Q: N, R: N, T: N, V: N, W: N, Y: N,

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[hide] Further associations between mutations and polymor... Invest Ophthalmol Vis Sci. 2011 Aug 5;52(9):6206-12. Print 2011 Aug. Aguirre-Lamban J, Gonzalez-Aguilera JJ, Riveiro-Alvarez R, Cantalapiedra D, Avila-Fernandez A, Villaverde-Montero C, Corton M, Blanco-Kelly F, Garcia-Sandoval B, Ayuso C
Further associations between mutations and polymorphisms in the ABCA4 gene: clinical implication of allelic variants and their role as protector/risk factors.
Invest Ophthalmol Vis Sci. 2011 Aug 5;52(9):6206-12. Print 2011 Aug., [PMID:21330655]

Abstract [show]
PURPOSE: Mutations in ABCA4 have been associated with autosomal recessive Stargardt disease, autosomal recessive cone-rod dystrophy, and autosomal recessive retinitis pigmentosa. The purpose of this study was to determine (1) associations among mutations and polymorphisms and (2) the role of the polymorphisms as protector/risk factors. METHODS: A case-control study was designed in which 128 Spanish patients and 84 control individuals were analyzed. Patient samples presented one or two mutated alleles previously identified using ABCR400 microarray and sequencing. RESULTS: A total of 18 previously described polymorphisms were studied in patients and control individuals. All except one presented a polymorphisms frequency higher than 5% in patients, and five mutations were found to have a frequency >5%. The use of statistical methods showed that the frequency of the majority of polymorphisms was similar in patients and controls, except for the IVS10+5delG, p.Asn1868Ile, IVS48+21C>T, and p.Arg943Gln polymorphisms. In addition, IVS48+21C>T and p.Arg943Gln were found to be in linkage disequilibrium with the p.Gly1961Glu and p.Arg602Trp mutations, respectively. CONCLUSIONS: Although the high allelic heterogeneity in ABCA4 and the wide spectrum of many common and rare polymorphisms complicate the interpretation of clinical relevance, polymorphisms were identified that may act as risk factors (p.Asn1868Ile) and others that may act as protection factors (p.His423Arg and IVS10+5 delG).

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85 Most Frequent ABCA4 Polymorphisms Found in Patients and Controls Exon Nucleotide Change Amino Acid Change Patients n (%) Allele Frequency n (%) Controls n (%) Allele Frequency n (%) P - IVS48؉21C>T SPLICE 13 (10.2) 13 (5.1) 0 (0.0) 0 (0.0) 0.003 - IVS10؉5 delG SPLICE 36 (28.1) 40 (15.6) 39 (46.4) 43 (25.6) 0.006 40 c.5603A>T p.Asn1868Ile 27 (21.1) 30 (11.7) 9 (10,7) 9 (5.3) 0.049 19 c.2828GϾA p.Arg943Gln 13 (10.2) 15 (5.8) 3 (3.6) 3 (1.8) 0.076 45 c.6249CϾT p.Ile2083Ile 14 (10.9) 15 (5.8) 16 (19.0) 18 (10.7) 0.098 49 c.6764GϾT p.Ser2255Ile 13 (10.2) 13 (5.1) 15 (17.9) 16 (9.5) 0.105 10 c.1268AϾG p.His423Arg 68 (53.1) 84 (32.8) 54 (64.3) 60 (35.7) 0.108 40 c.5682GϾC p.Leu1894Leu 70 (54.7) 90 (35.1) 37 (44.0) 41 (24.4) 0.130 42 c.5843CAϾTG p.Pro1948Leu 13 (10.2) 13 (5.1) 14 (16.7) 15 (8.9) 0.164 8 c.981CϾT p.Pro327Pro 2 (1.6) 2 (0.8) 0 (0.0) 0 (0.0) 0.250 6 c.635GϾA p.Arg212His 8 (6.3) 11 (4.3) 8 (9.5) 8 (4.7) 0.377 41 c.5814AϾG p.Leu1938Leu 40 (31.3) 48 (18.7) 31 (36.9) 35 (20.8) 0.394 44 c.6069CϾT p.Ile2023Ile 17 (13.3) 17 (6.6) 14 (16.7) 15 (8.9) 0.495 IVS33ϩ48CϾT SPLICE 109 (85.2) 170 (66.4) 74 (88.1) 93 (55.3) 0.542 28 c.4203CϾA/T p.Pro1401Pro 10 (7.8) 10 (3.9) 5 (6.0) 5 (2.9) 0.605 10 c.1269CϾT p.His423His 8 (6.3) 8 (3.1) 4 (4.8) 4 (2.4) 0.647 42 c.5844AϾG p.Pro1948Pro 36 (28.1) 42 (16.4) 23 (27.4) 25 (14.9) 0.906 46 c.6285TϾC p.Asp2095Asp 39 (30.5) 43 (16.8) 25 (29.8) 27 (16.1) 0.913 Variants revealing significant differences between both groups are shown in bold. Login to comment
86 the patient group: p.Asn1868Ile (P ϭ 0.013) and p.His423Arg (P ϭ 0 0.023) (Table 3). Login to comment
94 p.Arg212H is p.Pro327Pro p.H is423Arg p.H is423H is IVS10+5delG p.Arg602Trp p.Arg943G ln c.3211insG T p.Arg1129Leu p.Pro1401Pro IVS33+48C >Tp.Leu1894Leu p-Leu1938Leu p.Pro1948Leu p.Pro1948Pro p.G ly1961G lup.Leu2060Argp.Asp2095Asp IVS48+21C >T - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - p.Asn1868Ile p.Ile2023Ile p.Ile2083Ile p.Ser2255Ile PATIENTSCONTROLS FIGURE 1. Login to comment
109 Association between the Most Frequent ABCA4 Polymorphisms and Mutations Patients Variants Frequency P Status Predicted Effect Mutation, n (%) p.Arg1129Leu 34 (26.6) Present polymorphisms p.His423Arg 94.1% 0.000 Associated Risk IVS33؉48C>T 100% 0.011 Associated Risk IVS10ϩ5delG 20.6% 0.049 Associated Protector p.Leu1938Leu 17.6% 0.033 Associated Protector p.Ser2255Ile 2.9% 0.054 Associated Protector Mutation, n (%) p.Gly1961Glu 18 (14.1) Present polymorphisms p.Pro1948Pro 94.7% 0.000 Associated Risk p.Leu1938Leu 89.5% 0.000 Associated Risk p.Asp2095Asp 78.9% 0.000 Associated Risk IVS48؉21C>T 70.0% 0.000 Associated Risk IVS10؉5delG 57.9% 0.008 Associated Risk p.His423Arg 31.6% 0.016 Associated Protector p.Asn1868Ile 18.7% 0.039 Associated Protector Mutation, n (%) p.Arg602Trp 8 (6.3%) Present polymorphisms p.Arg943Gln 62.5% 0.000 Associated Risk p.Pro1401Pro 25% 0.044 Associated Protector p.Leu1938Leu 0% 0.041 Associated Protector Mutation, n (%) c.3211insGT 7 (5.5%) Present polymorphisms p.His423Arg 100% 0.021 Associated Risk p.Asn1868Ile 100% 0.000 Associated Risk IVS10ϩ5delG 0% 0.047 Associated Protector Mutation, n (%) p.Leu2060Arg 7 (5.5%) Present polymorphisms p.Leu1938Leu 100% 0.000 Associated Risk p.Pro1948Leu 100% 0.000 Associated Risk p.His423Arg 14.3% 0.019 Associated Protector TABLE 4. Login to comment
129 The p.Arg943Gln polymorphism is in linkage disequilibrium with the p.Arg602Trp mutation in Spanish STGD (P Ͻ 0.001, Table 3). Login to comment

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

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

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

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

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

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83 In our series, mainly consisting of patients coming from central Italy, G1961E was the most common mutant allele, in congruence with other studies performed in distinct dissimilar European populations.9,20 Nevertheless, the frequency of G1961E mutation (20.4% of our STGD alleles) was higher than in the other Italian Table 3 Summary of the polymorphic variants identified in the ABCR gene in our series of STGD Italian patients Location Polymorphic variants Number of alleles Exon 3 IVS3 þ 26a4g 14 Exon 5 D159 1 Exon 6 R212H 6 Exon 7 IVS7-32t4c 9 Exon 10 H423R 12 Exon 13 D644 1 Exon 14 IVS14 þ 50t4c 1 Exon 15 IVS15-13t4c 2 Exon 16 IVS16-13c4t 1 Exon 19 R943Q 3 Exon 20 L1988 1 Exon 23 Q1169 4 Exon 23 IVS23 þ 25g4a 2 Exon 24 T1176 6 Exon 24 K1182 3 Exon 28 P1401 1 Exon 33 IVS33-39t4c 2 Exon 34 IVS34 þ 16insgtt 4 Exon 38 D1817Q 7 Exon 40 N1868I 3 Exon 40 L1894 16 Exon 41 L1938 15 Exon 42 P1948 23 Exon 44 I2023 5 Exon 44 IVS44-16g4a 5 Exon 44 IVS44 þ 77g4a 1 Exon 45 I2083 5 Exon 46 D2095 19 Exon 48 IVS48 þ 21c4t 3 Exon 49 S2255I 5 studies where this mutation was detected in 11.110 and 9.7% 11 of the screened alleles. Login to comment

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

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

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

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

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

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111 Exon Nucleotide Change Effect STGD Families Frequency References IVS3 c.302+20C>T - 12 4.8% [6] IVS3 c.302+26A>G - 7,12,13,14 1.91% [6] 6 c.635G>A p.Arg212His 13,19 9.5% [15] IVS7 c.859+8T>C - 17 4.8% Present study 10 c.1268A>G p.His423Arg 2,4,5,6,10,11,12,13,14,18,19 53% [13] 10 c.1269C>T p.His423His 16 4.8% [13] IVS10 c.1356+5delG SPLICE 1,7,11,15,20 23.8% [13] IVS14 c.2161+47T>C - 18 4.8% Present study 19 c.2828G>A p.Arg943Gln 3,10,18,19 19.1% [5] IVS19 c.2919+34C>T - 12 4.8% Present study 20 c.2964T>C p.Leu988Leu 12 4.8% [6] IVS22 c.3326-19G>A - 2 4.8% Present study IVS33 c.4773+48C>T Splice 1,2,3,5,6,8,9,10,12,13,14,16,17,18,19,20 76.2% [13] 40 c.5603A>T p.Asn1868Ile 4,10,17 14.3% [6] 40 c.5682G>C p.Leu1894Leu 1,2,4,5,8,10,12,13,17,18 47.6% [6] 41 c.5814A>G p.Leu1938Leu 1,2,5,8,10,12,13,18 3.81% [6] 42 c.5843CA>TG/c.5843C>T p.Pro1948Leu 11 4.8% [14] 42 c.5844A>G p.Pro1948Pro 1,2,5,8,10,12,13 33.3% [14] 44 c.6069C>T p.Ile2023Ile 9,12,14,19 19.1% [6] 45 c.6249C>T p.Ile2083Ile 9,12,14,19 19.1% [5] 46 c.6285T>C p.Asp2095Asp 1,2,8,9,10,12,14,19 38.1% [14] IVS48 c.6769+21C>T SPLICE 1,10 9.5% [6] 49 c.6764G>T p.Ser2255Ile 1,9,14,19 19.1% [5] Several polymorphisms in exons and introns (IVS) throughout the entire ABCA4 gene were found in our study population. Login to comment
110 Exon Nucleotide Change Effect STGD Families Frequency References IVS3 c.302+20C>T - 12 4.8% [6] IVS3 c.302+26A>G - 7,12,13,14 1.91% [6] 6 c.635G>A p.Arg212His 13,19 9.5% [15] IVS7 c.859+8T>C - 17 4.8% Present study 10 c.1268A>G p.His423Arg 2,4,5,6,10,11,12,13,14,18,19 53% [13] 10 c.1269C>T p.His423His 16 4.8% [13] IVS10 c.1356+5delG SPLICE 1,7,11,15,20 23.8% [13] IVS14 c.2161+47T>C - 18 4.8% Present study 19 c.2828G>A p.Arg943Gln 3,10,18,19 19.1% [5] IVS19 c.2919+34C>T - 12 4.8% Present study 20 c.2964T>C p.Leu988Leu 12 4.8% [6] IVS22 c.3326-19G>A - 2 4.8% Present study IVS33 c.4773+48C>T Splice 1,2,3,5,6,8,9,10,12,13,14,16,17,18,19,20 76.2% [13] 40 c.5603A>T p.Asn1868Ile 4,10,17 14.3% [6] 40 c.5682G>C p.Leu1894Leu 1,2,4,5,8,10,12,13,17,18 47.6% [6] 41 c.5814A>G p.Leu1938Leu 1,2,5,8,10,12,13,18 3.81% [6] 42 c.5843CA>TG/c.5843C>T p.Pro1948Leu 11 4.8% [14] 42 c.5844A>G p.Pro1948Pro 1,2,5,8,10,12,13 33.3% [14] 44 c.6069C>T p.Ile2023Ile 9,12,14,19 19.1% [6] 45 c.6249C>T p.Ile2083Ile 9,12,14,19 19.1% [5] 46 c.6285T>C p.Asp2095Asp 1,2,8,9,10,12,14,19 38.1% [14] IVS48 c.6769+21C>T SPLICE 1,10 9.5% [6] 49 c.6764G>T p.Ser2255Ile 1,9,14,19 19.1% [5] Several polymorphisms in exons and introns (IVS) throughout the entire ABCA4 gene were found in our study population. Login to comment

[hide] Homozygosity for a novel ABCA4 founder splicing mu... Invest Ophthalmol Vis Sci. 2007 Sep;48(9):4308-14. Beit-Ya'acov A, Mizrahi-Meissonnier L, Obolensky A, Landau C, Blumenfeld A, Rosenmann A, Banin E, Sharon D
Homozygosity for a novel ABCA4 founder splicing mutation is associated with progressive and severe Stargardt-like disease.
Invest Ophthalmol Vis Sci. 2007 Sep;48(9):4308-14., [PMID:17724221]

Abstract [show]
PURPOSE: To clinically characterize and genetically analyze members of six families who reside in the same village and manifest a rare form of retinal degeneration. METHODS: Ophthalmic evaluation included a full clinical examination, perimetry, color vision testing, and electroretinography. Genomic DNA was screened for ABCA4 mutations with the use of microarray analysis and direct sequencing. RNA analysis was performed with RT-PCR and sequencing. RESULTS: The authors recruited 15 patients with a unique retinal disease who are members of six highly consanguineous Arab-Muslim families from a single village. During early stages of disease, funduscopic and angiographic findings as well as retinal function resemble those of Stargardt disease. However, later in life, severe, widespread cone-rod degeneration ensues. Marked progressive involvement of the retinal periphery distinguishes this phenotype from classic Stargardt disease. Genetic analysis of ABCA4 revealed two novel deletions, p.Cys1150del and c.4254-15del23. One patient, who was a compound heterozygote, manifested typical Stargardt disease. The remaining 14 patients were homozygote for the c.4254- 15del23 intronic deletion and had the progressive form of disease. We identified an identical ABCA4 haplotype in all alleles carrying this mutation, indicating a founder mutation. Detailed RT-PCR analysis in normal retina and lymphoblastoid cells revealed expression of the full-length ABCA4 transcript and three novel transcripts produced by alternative splicing. The full-length ABCA4 transcript, however, could not be detected in lymphoblastoid cells of affected homozygote patients. CONCLUSIONS: These results expand the genotype-phenotype correlation of ABCA4, showing that homozygosity for the novel c.4254-15del23 splicing mutation is associated with a severe progressive form of disease.

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88 To identify these mutations, we screened the DNA of two affected patients for all known ABCA4 sequence variants by using the Asper biotech ABCA4 mutation detection microarray.6 The screen revealed seven sequence changes (c.1269CϾT [p.His423His], c.1356ϩ5delG, c.4773ϩ48CϾT, c.6069CϾT [p.Ile2023Ile], c.6249CϾT [p.Ile2083Ile], c.6285TϾC [p.Asp2095Asp], and c.6764GϾT [p.Ser2255Ile]) that had been previously interpreted as nonpathogenic changes. 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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56 TABLE 1. Genetic Analyses of ABCA4 Mutations in Three Families with Autosomal Dominant Macular Dystrophy Family Allele 1 Allele 2 Haplotype AnalysisNucleotide Change Amino Acid Change Nucleotide Change Amino Acid Change ADDM-59 [5582G3A; 6764G3T] [G1961E; S22551] Excluded ADDM-92 466A3G I156V Not done ADDM-105 2828G3A R943Q Not done No change has been detected as allele 2. Login to comment
57 TABLE 2. Genetic Analyses of ABCA4 Mutations in 13 arCRD Families Family Allele 1 Allele 2 Haplotype AnalysisNucleotide Change Amino Acid Change Nucleotide Change Amino Acid Change ARDM-79 2888delG Frameshift 2888delG Frameshift Cosegregates ARDM-85 6764G3T S2255I (likely nonpathogenic) Not detected Not done* ARDM-86 2888delG Frameshift 2888delG Frameshift Cosegregates ARDM-99 4297G3A V1433I Not detected Not done* ARDM-126 [2828G3A; 5929G3A] [R943Q; G1977S] [2828G3A; 5929G3A] [R943Q; G1977S] Cosegregates ARDM-133 32T3C L11P 2888delG Frameshift Cosegregates ARDM-134 2828G3A R943Q Excluded ARDM-174 4918C3T R1640W c.6147؉2T3A Splice Cosegregates ARDM-176 2888delG Frameshift 6179T3G L2060R Cosegregates RP-267 5041del 15 pb Frameshift 5041del 15 pb Frameshift Cosegregates RP-577 1140T3A N380K Not detected Not done* SRP-964 2828G3A R943Q Not detected Not done* B210 2828G3A R943Q 2701A3G T901A Not done* The mutation detected by dHPLC is in bold. Login to comment
66 In family ADDM-59, a complex allele [G1961E; S2255I] was detected in the index patient, but not in her affected daughter, suggesting no cosegregation of the disease within the family. Login to comment
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
115 The last arCRD family studied also presented two missense mutations, namely T901A and R943Q, the latter described as reducing the ATPase activity in 40% and producing minimal defects in nucleotide binding,22 being categorized as a mild mutation. Login to comment
117 In all the cases, they were missense mutations (Table 1), although two of them (R943Q and S2255I) are still controversial: R943Q reduces the ATPase activity, and S2255I is supposed to have limited pathogenicity. Login to comment
118 Thus, such alleles would not be expected to cause disease if paired themselves, but could cause disease if paired with another allele of higher pathogenicity.25 Expression analysis of S2255I has not been reported, but, as proposed by Webster et al.,25 we cannot exclude a limited pathologic effect of this allele in those cases presenting a severer phenotype. Login to comment
123 In three families we identified only the controversial change S2255I, but as we pointed out before, we could not exclude this mutation as having a role in the pathogenesis of the disease. Login to comment
124 The percentage of allele detection was 13% to 16%, depending on the inclusion of the S2255I change. Login to comment
65 In family ADDM-59, a complex allele [G1961E; S2255I] was detected in the index patient, but not in her affected daughter, suggesting no cosegregation of the disease within 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
114 In all the cases, they were missense mutations (Table 1), although two of them (R943Q and S2255I) are still controversial: R943Q reduces the ATPase activity, and S2255I is supposed to have limited pathogenicity. Login to comment
120 In three families we identified only the controversial change S2255I, but as we pointed out before, we could not exclude this mutation as having a role in the pathogenesis of the disease. Login to comment
121 The percentage of allele detection was 13% to 16%, depending on the inclusion of the S2255I change. Login to comment

[hide] Severe autosomal recessive retinitis pigmentosa ma... Hum Genet. 2005 Dec;118(3-4):356-65. Epub 2005 Sep 28. Zhang Q, Zulfiqar F, Xiao X, Riazuddin SA, Ayyagari R, Sabar F, Caruso R, Sieving PA, Riazuddin S, Hejtmancik JF
Severe autosomal recessive retinitis pigmentosa maps to chromosome 1p13.3-p21.2 between D1S2896 and D1S457 but outside ABCA4.
Hum Genet. 2005 Dec;118(3-4):356-65. Epub 2005 Sep 28., [PMID:16189710]

Abstract [show]
A severe form of autosomal recessive retinitis pigmentosa (arRP) was identified in a large Pakistani family ascertained in the Punjab province of Pakistan. All affected individuals in the family had night blindness in early childhood, early complete loss of useful vision, and typical RP fundus changes plus macular degeneration. After exclusion of known arRP loci, a genome-wide scan was performed using microsatellite markers at about 10 cM intervals and calculating two-point lod scores. PCR cycle dideoxynucleotide sequencing was used to sequence candidate genes inside the linked region for mutations. RP in this family shows linkage to markers in a 10.5 cM (8.9 Mbp) region of chromosome 1p13.3-p21.2 between D1S2896 and D1S457. D1S485 yields the highest lod score of 6.54 at theta=0. Sequencing the exons and intron-exon boundaries of five candidate genes and six ESTs in this region, OLFM3, GNAI3, LOC126987, FLJ25070, DKFZp586G0123, AV729694, BU662869, BU656110, BU171991, BQ953690, and CA397743, did not identify any causative mutations. This novel locus lies approximately 4.9 cM (7.1 Mbp) from ABCA4, which is excluded from the linked region. Identification and study of this gene may help to elucidate the phenotypic diversity of arRP mapping to this region.

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132 However, choroidal atrophy in the posterior pole is much more Table 2 Two-point linkage results for markers in the ARRP region at 1p13.2-p21.2 Markers Position Lod score at h value Zmax hmax cM Mbpa 0.00 0.01 0.05 0.10 0.20 0.30 0.40 D1S2868 129.90 93.05 À¥ À1.96 0.40 1.07 1.19 0.81 0.29 1.24 0.16 D1S236 132.40 93.82 À¥ 1.03 2.07 2.22 1.88 1.27 0.56 2.22 0.10 D1S2664 133.00 95.66 À¥ 2.91 3.81 3.78 3.06 2.01 0.86 3.85 0.07 D1S2793 133.00 96.81 À¥ 3.26 4.14 4.08 3.29 2.17 0.96 4.17 0.07 D1S2808 135.20 98.97 À¥ 2.33 3.25 3.25 2.62 1.70 0.69 3.30 0.07 D1S2671 137.40 100.98 À¥ 3.47 4.34 4.29 3.48 2.34 1.07 4.38 0.07 D1S206 137.60 101.40 À¥ 2.16 2.54 2.44 1.90 1.23 0.52 2.54 0.05 D1S2896 137.30 101.68 À¥ 1.05 2.07 2.21 1.86 1.23 0.53 2.21 0.09 D1S495 140.80 102.27 3.35 4.57 4.76 4.42 3.39 2.17 0.93 4.80 0.03 D1S2699 140.70 104.49 1.52 2.77 3.06 2.86 2.14 1.29 0.46 3.06 0.04 D1S485 140.60 104.98 6.54 6.41 5.89 5.23 3.86 2.46 1.07 6.54 0.00 D1S429 140.50 105.41 3.70 4.90 5.06 4.68 3.56 2.25 0.94 5.11 0.03 D1S2759 140.30 105.56 3.70 5.25 5.41 5.01 3.85 2.49 1.09 5.46 0.03 D1S239 143.10 106.55 0.04 1.27 1.70 1.67 1.31 0.82 0.31 1.71 0.07 D1S248 143.30 106.87 3.41 4.63 4.82 4.48 3.45 2.23 0.97 4.85 0.04 D1S457 147.80 110.59 À¥ À4.63 À1.44 À0.30 0.42 0.45 0.20 0.74 0.80 D1S2726 149.00 110.90 À¥ À3.52 À0.47 0.51 0.97 0.81 0.41 0.97 0.21 a Build 35.1 (9-15-04) Table 3 Haplotypes of four affected individuals in the pedigree using the sequence changes in the ABCA4 gene Exon Nucleotide change Amino acid change Individual number 9 17 27 30 10 1268 A>G H423R A/A A/A A/A G/A 1269 C>T H423H T/T T/T C/C C/C delG IVS+5 Splice G/G G/G G/T G/T 19 2828 G>A R943Q A/A A/A G/G G/G 33 IVS+48 C>T Splice C/C C/C T/T C/T 45 6249 C>T I2083I C/C C/C T/C C/C 46 6285 T>C D2095D T/T T/T C/T T/T 48 6529 G>A D2177N G/G G/G G/G A/G 49 6764 G>T S2255I G/G G/G T/G G/G Italic-wild-type alleles; underlined-nucleotide substitutions which do not lead to the amino acid substitution and/or common polymorphisms; bold-nucleotide substitution which results in an amino acid substitution; the individual numbers in Table 3 are consistent with those in Figs. Login to comment
131 However, choroidal atrophy in the posterior pole is much more Table 2 Two-point linkage results for markers in the ARRP region at 1p13.2-p21.2 Markers Position Lod score at h value Zmax hmax cM Mbpa 0.00 0.01 0.05 0.10 0.20 0.30 0.40 D1S2868 129.90 93.05 &#a5; 1.96 0.40 1.07 1.19 0.81 0.29 1.24 0.16 D1S236 132.40 93.82 &#a5; 1.03 2.07 2.22 1.88 1.27 0.56 2.22 0.10 D1S2664 133.00 95.66 &#a5; 2.91 3.81 3.78 3.06 2.01 0.86 3.85 0.07 D1S2793 133.00 96.81 &#a5; 3.26 4.14 4.08 3.29 2.17 0.96 4.17 0.07 D1S2808 135.20 98.97 &#a5; 2.33 3.25 3.25 2.62 1.70 0.69 3.30 0.07 D1S2671 137.40 100.98 &#a5; 3.47 4.34 4.29 3.48 2.34 1.07 4.38 0.07 D1S206 137.60 101.40 &#a5; 2.16 2.54 2.44 1.90 1.23 0.52 2.54 0.05 D1S2896 137.30 101.68 &#a5; 1.05 2.07 2.21 1.86 1.23 0.53 2.21 0.09 D1S495 140.80 102.27 3.35 4.57 4.76 4.42 3.39 2.17 0.93 4.80 0.03 D1S2699 140.70 104.49 1.52 2.77 3.06 2.86 2.14 1.29 0.46 3.06 0.04 D1S485 140.60 104.98 6.54 6.41 5.89 5.23 3.86 2.46 1.07 6.54 0.00 D1S429 140.50 105.41 3.70 4.90 5.06 4.68 3.56 2.25 0.94 5.11 0.03 D1S2759 140.30 105.56 3.70 5.25 5.41 5.01 3.85 2.49 1.09 5.46 0.03 D1S239 143.10 106.55 0.04 1.27 1.70 1.67 1.31 0.82 0.31 1.71 0.07 D1S248 143.30 106.87 3.41 4.63 4.82 4.48 3.45 2.23 0.97 4.85 0.04 D1S457 147.80 110.59 &#a5; 4.63 1.44 0.30 0.42 0.45 0.20 0.74 0.80 D1S2726 149.00 110.90 &#a5; 3.52 0.47 0.51 0.97 0.81 0.41 0.97 0.21 a Build 35.1 (9-15-04) Table 3 Haplotypes of four affected individuals in the pedigree using the sequence changes in the ABCA4 gene Exon Nucleotide change Amino acid change Individual number 9 17 27 30 10 1268 A>G H423R A/A A/A A/A G/A 1269 C>T H423H T/T T/T C/C C/C delG IVS+5 Splice G/G G/G G/T G/T 19 2828 G>A R943Q A/A A/A G/G G/G 33 IVS+48 C>T Splice C/C C/C T/T C/T 45 6249 C>T I2083I C/C C/C T/C C/C 46 6285 T>C D2095D T/T T/T C/T T/T 48 6529 G>A D2177N G/G G/G G/G A/G 49 6764 G>T S2255I G/G G/G T/G G/G Italic-wild-type alleles; underlined-nucleotide substitutions which do not lead to the amino acid substitution and/or common polymorphisms; bold-nucleotide substitution which results in an amino acid substitution; the individual numbers in Table 3 are consistent with those in Figs. 1 and 2 and Table 1 obvious in the two families with ABCA4 mutations (Cremers et al. 1998; Klevering et al. 1999; Martinez-Mir et al. 1997, 1998). 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] Genotyping microarray (gene chip) for the ABCR (AB... Hum Mutat. 2003 Nov;22(5):395-403. Jaakson K, Zernant J, Kulm M, Hutchinson A, Tonisson N, Glavac D, Ravnik-Glavac M, Hawlina M, Meltzer MR, Caruso RC, Testa F, Maugeri A, Hoyng CB, Gouras P, Simonelli F, Lewis RA, Lupski JR, Cremers FP, Allikmets R
Genotyping microarray (gene chip) for the ABCR (ABCA4) gene.
Hum Mutat. 2003 Nov;22(5):395-403., [PMID:14517951]

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

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88 Several common polymorphisms were also included, mainly from the coding region (R212H, H423R, R943Q, N1868I, P1948L, S2255I). Login to comment

[hide] Analysis of the ABCR (ABCA4) gene in 4-aminoquinol... Am J Ophthalmol. 2001 Jun;131(6):761-6. Shroyer NF, Lewis RA, Lupski JR
Analysis of the ABCR (ABCA4) gene in 4-aminoquinoline retinopathy: is retinal toxicity by chloroquine and hydroxychloroquine related to Stargardt disease?
Am J Ophthalmol. 2001 Jun;131(6):761-6., [PMID:11384574]

Abstract [show]
PURPOSE: To determine if mutations in ABCR (ABCA4) are associated with chloroquine/hydroxychloroquine retinopathy. METHODS: DNA from eight patients with chloroquine or hydroxychloroquine retinopathy was studied. Controls were 80 individuals over age 65 years with normal retinal examinations. Ophthalmoscopy, color vision testing, visual fields, retinal photography, and fluorescein angiography were performed on the eight patients. Direct DNA sequencing of the exons and flanking intronic regions of the ABCR gene was completed for all patients. RESULTS: Clinical evaluation confirmed the diagnosis of chloroquine/hydroxychloroquine retinopathy and excluded Stargardt disease in each patient. Two patients had heterozygous ABCR missense mutations previously associated with Stargardt disease. None of the controls had these missense mutations. Three other patients had other missense polymorphisms. CONCLUSIONS: Some individuals who have ABCR mutations may be predisposed to develop retinal toxicity when exposed to chloroquine/hydroxychloroquine. We urge further study of a larger cohort of patients with chloroquine/hydroxychloroquine retinopathy.

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54 Subject 7 is also heterozygous for two missense polymorphisms: the transition 635G3A which encodes the substitution Arg212His, and the transversion 6764G3T which encodes the substitution Ser2255Ile. Login to comment
60 ABCR Coding Alterations in Patients With Chloroquine and Hydroxychloroquine Retinopathy Exon Nucleotide* Amino Acid* Patient Number 1 2 3 4 5 6 7 8 6 635 Arg212His G/G G/G G/G G/G G/G G/G A/G G/G 10 1268 His423Arg A/A A/A A/A G/G A/A A/A A/A A/A 1269 His423His C/C C/C C/C C/C C/C C/T C/T C/C 20 2964 Leu988Leu C/C C/C C/C C/C C/C C/C C/T C/C 23 3385 Arg1129Cys† C/C C/C C/T† C/C C/C C/C C/C C/C 24 3602 Leu1201Arg† T/T T/T T/T T/T T/T T/T T/G† T/T 28 4203 Pro1401Pro C/C C/C C/C C/A C/A C/C C/C C/C 40 5603 Asn1868Ile A/A A/A A/A A/T A/T A/A A/A A/A 5682 Leu1894Leu G/G G/C G/C G/C G/C G/G C/C G/G 41 5814 Leu1938Leu A/A A/G A/G A/A A/A A/A G/G A/A 42 5844 Pro1948Pro A/A A/G A/G A/A A/A A/A G/G A/A 44 6069 Ile2023Ile C/C C/C C/C C/C C/C C/T C/C C/T 45 6249 Ile2083Ile C/C C/C C/C C/C C/C C/T C/C C/T 46 6285 Asp2095Asp T/T T/T T/T T/T T/T T/T C/C T/C 6320 Arg2107His† G/G G/G G/G G/G G/G G/G A/A† G/G 49 6764 Ser2255Ile G/G G/G G/G G/G G/G G/G G/T G/T *Standard amino acid and nucleotide abbreviations are used. Login to comment
64 Subject 5 is heterozygous for the substitution Asn1868Ile, and subject 8 is heterozygous for the substitution Ser2255Ile. Login to comment
74 In addition, he is a carrier of two missense polymorphisms, Arg212His and Ser2255Ile. Login to comment
75 The Arg212His alteration was found in eight of 182 control chromosomes (4.4%), whereas the Ser2255Ile alteration was reported in six of 116 control chromosomes (5.2%). Login to comment

[hide] Spectrum of ABCA4 (ABCR) gene mutations in Spanish... Hum Mutat. 2001 Jun;17(6):504-10. Paloma E, Martinez-Mir A, Vilageliu L, Gonzalez-Duarte R, Balcells S
Spectrum of ABCA4 (ABCR) gene mutations in Spanish patients with autosomal recessive macular dystrophies.
Hum Mutat. 2001 Jun;17(6):504-10., [PMID:11385708]

Abstract [show]
The ABCA4 gene has been involved in several forms of inherited macular dystrophy. In order to further characterize the complex genotype-phenotype relationships involving this gene, we have performed a mutation analysis of ABCA4 in 14 Spanish patients comprising eight STGD (Stargardt), four FFM (fundus flavimaculatus), and two CRD (Cone-rod dystrophy) patients. SSCP (single-strand conformation polymorphism) analysis and DNA sequencing of the coding and 5' upstream regions of this gene allowed the identification of 16 putatively pathogenic alterations, nine of which are novel. Most of these were missense changes, and no patient was found to carry two null alleles. Overall, the new data agree with a working model relating the different pathogenic phenotypes to the severity of the mutations. When considering the information presented here together with that of previous reports, a picture of the geographic distribution of three particular mutations emerges. The R212C change has been found in French, Italian, Dutch, German, and Spanish but not in British patients. In the Spanish collection, R212C was found in a CRD patient, indicating that it may be a rather severe change. In contrast, c.2588G>C, a very common mild allele in the Dutch population, is rarely found in Southern Europe. Interestingly, the c.2588G>C mutation has been found in a double mutant allele together with the missense R1055W. Finally, the newly described L1940P was found in two unrelated Spanish patients, and may be a moderate to severe allele.

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77 These comprise two missense changes found also in control chromosomes that were described as polymorphisms by other authors (R943Q and S2255I). Login to comment
80 We examined the genomic sequences surrounding each of the changes looking for cryptic splice sites, and none was found, with the exception of c.1356+ TABLE 2. Summary of the Putative Polymorphisms Found in the Screening of the ABCA4 Gene Nucleotide change Exon/IVS Amino acid change No. of patients No. of controls Referencesa c.1239-14T->C IVS9 1 NT c.1239-63insC IVS9 1 NT c.1356+11delG IVS10 1 7/140 1 c.1762-54G->A IVS12 2 NT c.2829G->A E19 R943Q 1 8/70 2 c.3863-110G->C IVS26 1 0/50 c.4284G->A E29 T1466T 1 0/50 c.5461-50insA IVS38 1 NT c.5584+11C->G IVS39 1 NT c.5715-25C->A IVS40 1 NT c.5844A->G E42 P1948P 1 5/29 3 c.5843CA->TG E42 P1948L 1 NT 3 c.5835-43A->C IVS41 1 NT c.5835-11A->G IVS41 1 NT c.6249C->T E45 I2083I 2 NT 2 c.6285T->C E46 D2095D 1 NT 3 c.6480-21C->T IVS47 1 0/51 c.6730-5A->C IVS48 1 3/50 c.6764G->T E49 S2255I 2 6/26 2 c.6816+28G->C IVS49 1 4/14 a References: 1, Papaioannou et al. [2000]; 2, Allikmets et al. [1997]; 3, Maugeri et al. [1999]. 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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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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109 If the three most common missense variants (Asn1868Ile, Ser2255Ile, and Arg943Gln) were not included, missense variants were detected in 34 (9.3%) of 364 AMD alleles and 13 (6.7%) of 192 control alleles. Login to comment
130 However, the nonconservative subset was not more strongly associated with Stargardt disease than the conservative subset, largely because three of the nonconservative changes exhibited a prevalence in non-Stargardt alleles of more than 4% (Asn1868Ile, Arg943Gln, and Ser2255Ile). Login to comment
140 Two of these 13 were the common variants Ser2255Ile and Pro1948Leu. Login to comment
155 Three missense variants, Gly863Ala, Asn1868Ile, and Ser2255Ile, were significantly enriched among patients with Stargardt disease but not to the extent that would be expected if they were fully penetrant Stargardt alleles. Login to comment
165 The Ser2255Ile was found in 48 patients with Stargardt disease and was homozygous in 6 of these. Login to comment
168 The two variants Asn1868Ile and Ser2255Ile occurred together in seven patients with Stargardt disease, one being homozygous for Ser2255Ile and heterozygous for Asn1868Ile. Login to comment
169 They also occurred together in one patient with AMD who was homozygous for Ser2255Ile and heterozygous for Asn1868Ile. Login to comment
171 For instance, Asn1868Ile was always associated with CTC at codon 1894 (Leu3Leu). Login to comment
103 Thirty-Three Truncated and 98 Amino Acid-Changing Variants in the ABCA4 Gene Exon Nucleotide Change Effect (A) (B) AMD (n d1d; 182) Control (n d1d; 96) STGD (n d1d; 374) Allele Prevalence 2 106delT FS NS 0 0 1 b0d;0.01 2 160 af9; 1g 3 a Splice site NS 0 0 1 b0d;0.01 3 161G 3 A Cys54Tyr NS 0 0 6 b0d;0.01 3 179C 3 T Ala60Val NS 0 0 2 b0d;0.01 3 194G 3 A Gly65Glu NS 0 0 2 b0d;0.01 3 223T 3 G Cys75Gly NS 0 0 2 b0d;0.01 3 247delCAAA FS NS 0 0 2 b0d;0.01 3 298C 3 T Ser100Pro NS 0 0 1 b0d;0.01 5 454C 3 T Arg152Stop NS 0 0 2 b0d;0.01 6 574G 3 A Ala192Thr NS 0 0 1 b0d;0.01 6 618C 3 G Ser206Arg NS 0 0 3 b0d;0.01 6 634C 3 T Arg212Cys 0.02 Yes 0 0 7 0.01 6 635G 3 A Arg212His NS 2 2 6 0.01 6 658C 3 T Arg220Cys NS 0 0 2 b0d;0.01 6 661delG FS NS 0 0 1 b0d;0.01 666delAAAGACGGTGC 6 GC FS NS 0 0 1 b0d;0.01 6 746A 3 C Asp249Gly NS 0 0 1 b0d;0.01 8 899C 3 A Thr300Asn NS 0 0 1 b0d;0.01 8 997C 3 T Arg333Trp NS 0 0 1 b0d;0.01 9 1140T 3 A Asn380Lys NS 0 0 1 b0d;0.01 9 1222C 3 T Arg408Stop NS 0 0 1 b0d;0.01 10 1268A 3 G His423Arg NS 1 0 7 0.01 10 1335C 3 G Ser445Arg NS 0 0 1 b0d;0.01 10 1344delG FS NS 0 0 1 b0d;0.01 11 1411G 3 A Glu471Lys NS 0 0 3 b0d;0.01 11 1513delATCAC FS NS 0 0 1 b0d;0.01 12 1622T 3 C Leu541Pro 0.001 Yes 0 0 11 0.01 13 1804C 3 T Arg602Trp NS 0 0 3 b0d;0.01 13 1805G 3 A Arg602Gln NS 0 0 1 b0d;0.01 13 1819G 3 T Gly607Trp NS 0 0 1 b0d;0.01 13 1823T 3 A Phe608Ile NS 0 0 1 b0d;0.01 13 1927G 3 A Val643Met NS 0 0 1 b0d;0.01 14 1989G 3 T Trp663Stop NS 0 0 1 b0d;0.01 14 2005delAT FS NS 0 0 3 b0d;0.01 14 2041C 3 T Arg681Stop NS 0 0 2 b0d;0.01 14 2147C 3 T Thr716Met NS 0 0 1 b0d;0.01 15 2291G 3 A Cys764Tyr NS 0 0 1 b0d;0.01 15 2294G 3 A Ser765Asn NS 0 0 1 b0d;0.01 15 2300T 3 A Val767Asp NS 0 0 2 b0d;0.01 16 2385del16bp FS NS 0 0 1 b0d;0.01 16 2453G 3 A Gly818Glu NS 0 0 1 b0d;0.01 16 2461T 3 A Trp821Arg NS 0 0 1 b0d;0.01 16 2546T 3 C Val849Ala NS 0 0 4 b0d;0.01 16 2552G 3 A Gly851Asp NS 0 0 1 b0d;0.01 16 2560G 3 A Ala854Thr NS 0 0 1 b0d;0.01 17 2588G 3 C Gly863Ala 0.0006 No 2 2 28 0.02 17 2617T 3 C Phe873Leu NS 0 0 1 b0d;0.01 18 2690C 3 T Thr897Ile NS 0 0 1 b0d;0.01 18 2701A 3 G Thr901Ala NS 0 1 0 b0d;0.01 18 2703A 3 G Thr901Arg NS 0 0 2 b0d;0.01 19 2828G 3 A Arg943Gln NS 20 13 37 0.05 19 2883delC FS NS 0 0 1 b0d;0.01 20 2894A 3 G Asn965Ser NS 0 0 3 b0d;0.01 19 2912C 3 A Thr971Asn NS 0 0 1 b0d;0.01 19 2915C 3 A Thr972Asn NS 0 0 1 b0d;0.01 20 2920T 3 C Ser974Pro NS 0 0 1 b0d;0.01 20 2966T 3 C Val989Ala NS 0 0 2 b0d;0.01 20 2977del8bp FS NS 0 0 1 b0d;0.01 20 3041T 3 G Leu1014Arg NS 0 0 1 b0d;0.01 21 3055A 3 G Thr1019Ala NS 0 0 1 b0d;0.01 21 3064G 3 A Glu1022Lys NS 0 0 1 b0d;0.01 21 3091A 3 G Lys1031Glu NS 0 0 1 b0d;0.01 21 3113G 3 T Ala1038Val 0.001 Yes 1 0 17 0.01 22 3205insAA FS NS 0 0 1 b0d;0.01 22 3261G 3 A Glu1087Lys NS 0 0 2 b0d;0.01 22 3322C 3 T Arg1108Cys 0.04 Yes 0 0 6 b0d;0.01 22 3323G 3 A Arg1108His NS 0 0 1 b0d;0.01 23 3364G 3 A Glu1122Lys NS 0 0 1 b0d;0.01 (continues) Exon Nucleotide Change Effect (A) (B) AMD (n d1d; 182) Control (n d1d; 96) STGD (n d1d; 374) Allele Prevalence 23 3386G 3 T Arg1129Leu NS 0 0 3 b0d;0.01 24 3531C 3 A Cys1158Stop NS 0 0 1 b0d;0.01 25 3749T 3 C Leu1250Pro NS 0 0 1 b0d;0.01 26 3835delGATTCT FS NS 0 0 1 b0d;0.01 27 3940C 3 A Pro1314Thr NS 0 1 0 b0d;0.01 28 4139C 3 T Pro1380Leu 0.001 Yes 0 0 10 0.01 28 4222T 3 C Trp1408Arg NS 0 0 2 b0d;0.01 28 4223G 3 T Trp1408Leu NS 0 0 2 b0d;0.01 28 4234C 3 T Gln1412stop NS 0 0 1 b0d;0.01 29 4297G 3 A Val1433Ile NS 1 0 0 b0d;0.01 29 4319T 3 C Phe1440Ser NS 0 0 1 b0d;0.01 30 4353 afa; 1g 3 t Splice site NS 0 0 1 b0d;0.01 30 4457C 3 T Pro1486Leu NS 0 0 1 b0d;0.01 30 4462T 3 C Cys1488Arg NS 0 0 3 b0d;0.01 30 4463G 3 T Cys1488Phe NS 0 0 2 b0d;0.01 30 4469G 3 A Cys1490Tyr NS 0 0 3 b0d;0.01 30 4531insC FS NS 0 0 2 b0d;0.01 32 4538A 3 G Gln1513Arg NS 0 0 1 b0d;0.01 30 4539 af9; 1g 3 t Splice site NS 0 0 1 b0d;0.01 31 4574T 3 C Leu1525Pro NS 0 0 1 b0d;0.01 33 4733delGTTT FS NS 0 0 1 b0d;0.01 4859delATAACAinsTCC 35 T FS NS 0 0 1 b0d;0.01 36 4909G 3 A Ala1637Thr NS 0 0 1 b0d;0.01 35 4918C 3 T Arg1640Trp NS 0 0 1 b0d;0.01 35 4919G 3 A Arg1640Gln NS 0 0 1 b0d;0.01 35 4954T 3 G Tyr1652Asp NS 0 0 1 b0d;0.01 36 5077G 3 A Val1693Ile NS 0 0 1 b0d;0.01 36 5186T 3 C Leu1729Pro NS 0 0 2 b0d;0.01 36 5206T 3 C Ser1736Pro NS 0 0 1 b0d;0.01 36 5212del11bp FS NS 0 0 1 b0d;0.01 37 5225delTGGTGGTGGGC FS NS 0 0 1 b0d;0.01 del LPA 37 5278del9bp 1760 NS 0 0 1 b0d;0.01 37 5288delG FS NS 0 0 1 b0d;0.01 38 5395A 3 G Asn1799Asp NS 0 0 1 b0d;0.01 38 5451T 3 G Asp1817Glu NS 1 0 4 b0d;0.01 39 5584 af9; 5g 3 a Splice site 0.02 Yes 0 0 6 b0d;0.01 40 5603A 3 T Asn1868Ile 0.0006 No 20 7 79 0.08 40 5651T 3 A Val1884GLu NS 0 0 1 b0d;0.01 40 5657G 3 A Gly1886Glu NS 0 0 1 b0d;0.01 40 5687T 3 A Val1896Asp NS 0 0 1 b0d;0.01 40 5693G 3 A Arg1898His NS 0 0 1 b0d;0.01 40 5714 af9; 5g 3 a Splice site NS 0 0 1 b0d;0.01 42 5843CA 3 TG Pro1948Leu NS 11 7 28 0.04 42 5882G 3 A Gly1961Glu b0d;0.0001 Yes 1 0 43 0.03 43 5908C 3 T Leu1970Phe NS 1 0 1 b0d;0.01 43 5917delG FS NS 0 0 1 b0d;0.01 44 6079C 3 T Leu2027Phe 0.01 Yes 0 0 9 0.01 44 6088C 3 T Arg2030Stop NS 0 0 2 b0d;0.01 44 6089G 3 A Arg2030Gln NS 0 0 1 b0d;0.01 44 6112A 3 T Arg2038Trp NS 0 0 1 b0d;0.01 45 6148A 3 C Val2050Leu NS 1 0 0 b0d;0.01 46 6212A 3 T Tyr2071Phe NS 0 0 1 b0d;0.01 45 6229C 3 T Arg2077Trp NS 0 0 2 b0d;0.01 46 6320G 3 A Arg2107His 0.01 Yes 0 0 10 0.01 46 6383A 3 G His2128Arg NS 0 0 1 b0d;0.01 47 6446G 3 T Arg2149Leu NS 0 0 1 b0d;0.01 47 6449G 3 A Cys2150Tyr NS 0 0 5 b0d;0.01 48 6529G 3 A Asp2177Asn NS 2 0 0 b0d;0.01 48 6686T 3 C Leu2229Pro NS 0 0 1 b0d;0.01 48 6707delTCACACAG FS NS 0 0 1 b0d;0.01 48 6729 af9; 1g 3 a Splice site NS 0 0 1 b0d;0.01 49 6764G 3 T Ser2255Ile 0.009 No 16 4 54 0.06 49 6788G 3 T Arg2263Leu NS 0 0 1 b0d;0.01 (A) The probability under the null hypothesis of similar prevalence of each variant in Stargardt (STGD) compared with non-STGD alleles (two-tailed Fisher`s exact test); (B) compatability of the variant existing in a ratio of 100:1 in STGD to control alleles, calculated using the binomial distribution. 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110 If the three most common missense variants (Asn1868Ile, Ser2255Ile, and Arg943Gln) were not included, missense variants were detected in 34 (9.3%) of 364 AMD alleles and 13 (6.7%) of 192 control alleles. Login to comment
131 However, the nonconservative subset was not more strongly associated with Stargardt disease than the conservative subset, largely because three of the nonconservative changes exhibited a prevalence in non-Stargardt alleles of more than 4% (Asn1868Ile, Arg943Gln, and Ser2255Ile). Login to comment
141 Two of these 13 were the common variants Ser2255Ile and Pro1948Leu. Login to comment
156 Three missense variants, Gly863Ala, Asn1868Ile, and Ser2255Ile, were significantly enriched among patients with Stargardt disease but not to the extent that would be expected if they were fully penetrant Stargardt alleles. Login to comment
167 The Ser2255Ile was found in 48 patients with Stargardt disease and was homozygous in 6 of these. Login to comment
170 The two variants Asn1868Ile and Ser2255Ile occurred together in seven patients with Stargardt disease, one being homozygous for Ser2255Ile and heterozygous for Asn1868Ile. Login to comment

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

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

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106 351 Table 2 Novel and previously reported polymorphic sites identified in the ABCR gene in late-onset STGD subjects and controls (bold novel polymorphic sites) Exon Nucleotide alteration Predicted AA change STGD1 chromosomes Control chromosomes P value Reference 6 635 GÆA R212H 1/50 Simonelli et al. (2000) 7 IVS6-32 TÆC 4/48 N. F. Shroyer et al. (in preparation) 10 IVS9-14CÆÆÆÆT 22/50 (44%) 18/166 (10.8%) P<0.001 Present study 10 1268AÆG H423R 10/50 (20%) 46/170 (27%) P<0.4 Rivera et al. (2000) 10 1269CÆT H423H 4/50 (8%) 7/170 (4%) P<0.2 Rivera et al. (2000) 10 IVS10+11delG 16/50 (32%) 57/170 (33.5%) P>0.5 Papaioannou et al. (2000) 19 2828 GÆA R943Q 4/50 Allikmets et al. (1997b) 28 4203 CÆA P1401P 7/50 Maugeri et al. (1999) 33 IVS33+48TÆÆÆÆC 22/50 (44%) 48/114 (42%) P<0.5 Present study 39 IVS38-10CÆT 1/48 Maugeri et al. (1999) 40 5603AÆT N1868I 8/48 Stone et al. (1998) 41 5814AÆG L1938L 3/50 N. F. Shroyer et al. (in preparation) 42 IVS41-44CÆA 3/48 N. F. Shroyer et al. (in preparation) 42 IVS41-11GÆA 3/48 Maugeri et al. (1999) 42 5844AÆG P1948P 2/48 Maugeri et al. (1999) 44 IVS43-16GÆA 1/48 N. F. Shroyer et al. (in preparation) 44 6069CÆT I2023I 4/50 Allikmets et al. (1997b) 45 6249CÆT I2083I 4/50 Maugeri et al. (1999) 45 IVS45+7GÆA 5/50 (10%) 9/160 (5.6%) P>0.1 Papaioannou et al. (2000) 49 IVS48-3TÆC 3/50 (6%) 10/170 (5.9%) P>0.9 Maugeri et al. (1999) 49 6764GÆT S2255I 3/50 Allikmets et al. (1997b) 49 IVS49+27GÆC 2/48 Papaioannou et al. (2000) All missense mutations in late-onset STGD1 occur outside known functional regions of ABCR The positions of late-onset associated ABCR missense mutations were placed on the predicted ABCR structure that includes four regions of known function (transmembrane and ATP-binding domains in each of two symmetric halves of the protein). Login to comment

[hide] ABCR gene analysis in familial exudative age-relat... Invest Ophthalmol Vis Sci. 2000 Jan;41(1):244-7. Souied EH, Ducroq D, Rozet JM, Gerber S, Perrault I, Munnich A, Coscas G, Soubrane G, Kaplan J
ABCR gene analysis in familial exudative age-related macular degeneration.
Invest Ophthalmol Vis Sci. 2000 Jan;41(1):244-7., [PMID:10634626]

Abstract [show]
PURPOSE: Identification of genetic factors in the pathogenesis of age-related macular degeneration (AMD) is of crucial importance in this common cause of blindness. Mutations in the Stargardt disease gene (ABCR) were previously reported in patients with atrophic forms of AMD. The purpose of this study was to analyze familial segregation of ABCR gene mutations in 52 unrelated multiplex cases of exudative AMD. METHODS: A complete ophthalmological examination including visual acuity measurement, fundus examination, and fluorescein angiography (FA) was performed on each exudative AMD patient. The entire coding sequence of the ABCR gene was analyzed using a combination of single-strand conformation polymorphism and confirmatory sequencing of the exons showing an abnormal pattern of migration. RESULTS: Six heterozygous missense changes were identified. A lack of familial segregation was observed in 4 of 6 codon changes (Arg943Gln, Val1433Ile, Pro1948Leu, and Ser2255Ile). Conversely, 2 codon changes cosegregated with the disease in 2 small families: Pro940Arg and Leu1970Phe. CONCLUSIONS: The authors believe that segregation of the ABCR gene mutations with familial cases of AMD has not yet been shown. The analysis of familial segregation allowed the authors to exclude 4 of 6 codon changes as disease-causing mutations. Furthermore, it was shown here that the ABCR gene may be rarely involved in exudative AMD, with at best 2 of 52 familial cases (4%) related to this susceptibility factor.

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8 A lack of familial segregation was observed in 4 of 6 codon changes (Arg943Gln, Val1433Ile, Pro1948Leu, and Ser2255Ile). Login to comment
40 The heterozygous codon changes observed were Pro940Arg, Arg943Gln (2 families), Pro1948Leu (2 families), Leu1970Phe, Val1433Ile, and Ser2255Ile. Login to comment
41 The Arg943Gln, Pro1948Leu, and Ser2255Ile substitutions were observed in the control group: in 3 of 90, 3 of 90, and 1 of 90, respectively. Login to comment
43 No cosegregation of the base substitution with the disease was observed in the families harboring either Arg943Gln, Val1433Ile, Pro1948Leu, or Ser2255Ile changes. Login to comment
53 In these studies, the Arg943Gln and Ser2255Ile codon changes have been reported as polymorphisms. Login to comment
54 Here, the lack of detection of Arg943Gln, Pro1948Leu, and Ser2255Ile in controls was not particularly meaningful and did not permit us to establish statistical significance. Login to comment
63 First, a lack of segregation was observed, for the Arg943Gln, Val1433Ile, Pro1948Leu, and Ser2255Ile changes. Login to comment

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

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

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85 In addition to screening for the previously reported variants, we screened our population for the five most common ABCR polymorphisms reported by Allikmets et al31 (U843G, D8464H, G863A, R934Z, S2255I) and failed to identify any of these particular polymorphisms in our study. Login to comment

[hide] Allelic variation in ABCR associated with Stargard... Nat Genet. 1998 Dec;20(4):328-9. Stone EM, Webster AR, Vandenburgh K, Streb LM, Hockey RR, Lotery AJ, Sheffield VC
Allelic variation in ABCR associated with Stargardt disease but not age-related macular degeneration.
Nat Genet. 1998 Dec;20(4):328-9., [PMID:9843201]

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23 The 3 common variants (Asn1868Ile, Arg943Gln and Ser2255Ile) were all present in more than 4% of all 3 groups. Login to comment
69 Three non-conservative variants (Asn1868Ile, Arg943Gln and Ser2255Ile) were very common (>4%) in all three groups. Login to comment

[hide] Mutation of the Stargardt disease gene (ABCR) in a... Science. 1997 Sep 19;277(5333):1805-7. Allikmets R, Shroyer NF, Singh N, Seddon JM, Lewis RA, Bernstein PS, Peiffer A, Zabriskie NA, Li Y, Hutchinson A, Dean M, Lupski JR, Leppert M
Mutation of the Stargardt disease gene (ABCR) in age-related macular degeneration.
Science. 1997 Sep 19;277(5333):1805-7., [PMID:9295268]

Abstract [show]
Age-related macular degeneration (AMD) is the leading cause of severe central visual impairment among the elderly and is associated both with environmental factors such as smoking and with genetic factors. Here, 167 unrelated AMD patients were screened for alterations in ABCR, a gene that encodes a retinal rod photoreceptor protein and is defective in Stargardt disease, a common hereditary form of macular dystrophy. Thirteen different AMD-associated alterations, both deletions and amino acid substitutions, were found in one allele of ABCR in 26 patients (16%). Identification of ABCR alterations will permit presymptomatic testing of high-risk individuals and may lead to earlier diagnosis of AMD and to new strategies for prevention and therapy.

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110 Alteration AMD STGD1 General population V643G 1/167 (0.6%) 0/98 (0%) 1/80 (1.25%) D846H 0/167 (0%) 1/98 (1%) 1/50 (2%) G863A 1/167 (0.6%) 13/150 (8.7%) 2/220 (0.9%) R943Q 6/127 (4.7%) 4/47 (9.5%) 13/80 (16.25%) S2255I 24/167 (14.4%) 8/98 (8%) 6/58 (10.3%) SCIENCE ⅐ VOL. Login to comment
107 Alteration AMD STGD1 General population V643G 1/167 (0.6%) 0/98 (0%) 1/80 (1.25%) D846H 0/167 (0%) 1/98 (1%) 1/50 (2%) G863A 1/167 (0.6%) 13/150 (8.7%) 2/220 (0.9%) R943Q 6/127 (4.7%) 4/47 (9.5%) 13/80 (16.25%) S2255I 24/167 (14.4%) 8/98 (8%) 6/58 (10.3%) SCIENCE z VOL. 277 z 19 SEPTEMBER 1997 z www.sciencemag.org which map primarily to the highly conserved ATP-binding regions of the ABCR protein, AMD alterations were found outside these domains (Fig. 1). Login to comment

[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.

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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
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
126 Interestingly, five out of 46 mutant alleles (11%) were complex alleles (p.R18W &#fe; p.S2255I; p.R602W &#fe; p.R943W; p.R943W &#fe; p.N1868I; p.G818E &#fe; p.E1942Q; and p.R1443H &#fe; p.S2255I), a frequency that is in agreement with previous reports (Lewis et al., 1999; Shroyer et al., 2001; Zernant et al., 2011). Login to comment
138 It is important to make note that three of the variants identified in this work, p.R943Q, p.N1868I, and p.S2255I have an allele frequency in the NHLBI Exome Sequencing Project of 3.2%, 4.8%, and 19% respectively, and thus they are most probably non-pathogenic variants. Login to comment
139 However, with the exception of sporadic case #7 who was homozygous for p.S2255I (sporadic case #7 in Table 1), all remaining 4 patients carrying one of such mutations also carry two additional deleterious ABCA4 mutations (sporadic cases #4, #3, and #20 in Table 1) or a null allele (p.E89*) combined with p.R943Q and p.N1868I (sporadic case #8). Login to comment

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

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

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

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

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

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80 Thorough search of the literature and four distinct population-derived exome/genome variant databases, including a database of the Polish population showed that four of the ABCA4 variants, i.e. p.R212H, p.H423R, c.6282&#fe;7G>A and p.S2255I have a high frequency (at least 3%) in the general population (Allikmets et al., 1997; Maugeri et al., 1999; Rivera et al., 2000). Login to comment
142 ABCA4 variant Patients Controls Present study ZGM 1000 Genomes ESP6500 ExAC c.635G>A 2.17% 3.82% 5.17% 3.41% 3.79% p.R212H (4/184) (45/1178) (52/1006) (293/8600) (2791/73,710) p &#bc; 0.39 p &#bc; 0.09 p &#bc; 0.48 p &#bc; 0.34 c.1268A>G 20.11% 29.90% 29.13% 30.94% 29.66% p.H423R (37/184) (354/1184) (293/1006) (2661/8600) (22,085/74,456) p < 0.01 p < 0.0001 p < 0.0001 p < 0.0001 c.6282&#fe;7G>A 4.89% 7.84% 5.86% 6.78% 5.92% splice site mutation (9/184) (93/1186) (59/1006) (583/8600) (4378/74,008) p &#bc; 0.18 p &#bc; 0.73 p &#bc; 0.39 p &#bc; 0.67 c.6764G>T 2.17% 4.41% 4.57% 4.65% 3.77% p.S2255I (4/184) (52/1178) (46/1006) (400/8600) (2802/74,338) p &#bc; 0.23 p &#bc; 0.16 p &#bc; 0.16 p &#bc; 0.35 c.1654G>A 1.09% 1.01% 0.10% 0.37% 0.37% p.V552I (2/184) (12/1188) (1/1006) (32/8600) (273/74,448) p &#bc; 1 p &#bc; 0.06 p &#bc; 0.34 p &#bc; 0.32 ZGM: exome data for the Polish population; 1000 Genomes: 1000 Genomes Project (http://www.1000genomes.org/); ESP6500: NHLBI GO Exome Sequencing Project (http:// evs.gs.washington.edu/EVS/); ExAC: Exome Aggregation Consortium (http://exac.broadinstitute.org/); The number of variant and total alleles detected is given in brackets. Login to comment