ABCMdb

ABCA4 p.Arg2038Trp

ClinVar:	c.6112C>T , p.Arg2038Trp ? , not provided
Predicted by SNAP2:	A: D (75%), C: D (75%), D: D (75%), E: D (71%), F: D (75%), G: D (71%), H: D (63%), I: D (75%), K: N (61%), L: D (75%), M: D (75%), N: D (53%), P: D (71%), Q: D (63%), S: D (59%), T: D (53%), V: D (75%), W: D (95%), Y: D (71%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: N, L: D, M: D, N: D, P: D, Q: D, S: D, T: D, V: D, W: D, Y: D,

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[hide] Molecular diagnosis of putative Stargardt disease ... BMC Med Genet. 2012 Aug 3;13:67. Strom SP, Gao YQ, Martinez A, Ortube C, Chen Z, Nelson SF, Nusinowitz S, Farber DB, Gorin MB
Molecular diagnosis of putative Stargardt disease probands by exome sequencing.
BMC Med Genet. 2012 Aug 3;13:67., [PMID:22863181]

Abstract [show]
ABSTRACT: BACKGROUND: The commonest genetic form of juvenile or early adult onset macular degeneration is Stargardt Disease (STGD) caused by recessive mutations in the gene ABCA4. However, high phenotypic and allelic heterogeneity and a small but non-trivial amount of locus heterogeneity currently impede conclusive molecular diagnosis in a significant proportion of cases. METHODS: We performed whole exome sequencing (WES) of nine putative Stargardt Disease probands and searched for potentially disease-causing genetic variants in previously identified retinal or macular dystrophy genes. Follow-up dideoxy sequencing was performed for confirmation and to screen for mutations in an additional set of affected individuals lacking a definitive molecular diagnosis. RESULTS: Whole exome sequencing revealed seven likely disease-causing variants across four genes, providing a confident genetic diagnosis in six previously uncharacterized participants. We identified four previously missed mutations in ABCA4 across three individuals. Likely disease-causing mutations in RDS/PRPH2, ELOVL, and CRB1 were also identified. CONCLUSIONS: Our findings highlight the enormous potential of whole exome sequencing in Stargardt Disease molecular diagnosis and research. WES adequately assayed all coding sequences and canonical splice sites of ABCA4 in this study. Additionally, WES enables the identification of disease-related alleles in other genes. This work highlights the importance of collecting parental genetic material for WES testing as the current knowledge of human genome variation limits the determination of causality between identified variants and disease. While larger sample sizes are required to establish the precision and accuracy of this type of testing, this study supports WES for inherited early onset macular degeneration disorders as an alternative to standard mutation screening techniques.

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55 Table 1 Clinical Information and Genetic Findings of Putative Stargardt Disease Cases\ SampleAge Sex Acuity OD Acuity OS Clinical Notes ERG Findings Color vision ABCA4 variants PRPH2 variants Other variants STGD-01 19 Male 20/400 20/160 Peripapillary sparing, discrete flecks; nummular atrophy Normal rod Abnormal cone No testing p.N965S p.R2038W . Login to comment
105 Exome sequencing identified two missense variants (p.N965S and p.R2038W) previously reported as disease-causing in STGD [19]. Login to comment
75 Table 1 Clinical Information and Genetic Findings of Putative Stargardt Disease Cases Sample Age Sex Acuity OD Acuity OS Clinical Notes ERG Findings Color vision ABCA4 variants PRPH2 variants Other variants STGD-01 19 Male 20/400 20/160 Peripapillary sparing, discrete flecks; nummular atrophy Normal rod Abnormal cone No testing p.N965S p.R2038W . Login to comment
101 Exome sequencing identified two missense variants (p.N965S and p.R2038W) previously reported as disease-causing in STGD [19]. Login to comment

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

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

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

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

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

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

[hide] Interaction of the nucleotide binding domains and ... Biochemistry. 2006 Mar 21;45(11):3813-23. Biswas-Fiss EE
Interaction of the nucleotide binding domains and regulation of the ATPase activity of the human retina specific ABC transporter, ABCR.
Biochemistry. 2006 Mar 21;45(11):3813-23., [PMID:16533065]

Abstract [show]
We report here a novel regulation of the ATPase activity of the human retina specific ATP binding cassette transporter (ABC), ABCR, by nucleotide binding domain interactions. We also present evidence that recombinant nucleotide binding domains of ABCR interact in vitro in the complete absence of transmembrane domains (TMDs). Although similar domain-domain interactions have been described in other ABC transporters, the roles of such interactions on the enzymatic mechanisms of these transporters have not been demonstrated experimentally. A quantitative analysis of the in vitro interactions as a function of the nucleotide-bound state demonstrated that the interaction takes place in the absence of nucleotide as well as in the presence of ATP and that it only attenuates in the ADP-bound state. Analysis of the ATPase activities of these proteins in free and complex states indicated that the NBD1-NBD2 interaction significantly influences the ATPase activity. Further investigation, using site-specific mutants, showed that mutations in NBD2 but not NBD1 led to the alteration of the ATPase activity of the NBD1.NBD2 complex and residue Arg 2038 is critical to this regulation. These data indicate that changes in the oligomeric state of the nucleotide binding domains of ABCR are coupled to ATP hydrolysis and might represent a possible signal for the TMDs of ABCR to export the bound substrate. Furthermore, the data support a mechanistic model in which, upon binding of NBD2, NBD1 binds ATP but does not hydrolyze it or does so with a significantly reduced rate.

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36 For example, the mutations P940R and R2038W are each localized to the nucleotide binding domains, NBD1 and NBD2, respectively. Login to comment
38 On the other hand, R2038W has been observed in individuals afflicted with Stargardt macular dystrophy, an aggressive form of degeneration, striking individuals in early adulthood and rapidly leading to blindness. Login to comment
74 The following complementary oligonucleotides were used as mutagenic primers to generate the mutant NBD1 and NBD2 proteins: NBD1Pro940Arg (5'-GGT AAA GAT TTT TGA GCG CTG TGG CCG GCC AGC TG-3'), NBD1 Walker A, K969A, T970A (5'-CAA TGG AGC TGG GGC AGC CAC CAC CTT GTC CAT CC-3'), NBD2 Walker A, K1978A, T1979A (5'-GAA TGG TGC CGG CGC AGC AAC CAC ATT CAA GAT GC-3'), and NBD2 R2038W (5'-CTT TAC CTT TAT GCC AGG CTT CGA GGT GTA CCA GC-3'). Login to comment
154 The Mutation R2038W Is Associated with a Reduced Affinity of NBD1-NBD2 Interaction and the Loss of ADP Modulation. Login to comment
156 Earlier, we had carried out a detailed analysis of the dynamics of ATP binding and hydrolysis of the NBD2 polypeptide harboring the R2038W mutation. Login to comment
171 Attenuation of the ATPase ActiVity by Nucleotide Binding Domain Interaction Is Altered in the Stargardt Mutant R2038W. Login to comment
172 The NBD2 mutation, R2038W, leads to significant reductions in the rate of ATP hydrolysis as well as the affinity of ATP binding (67). Login to comment
173 To evaluate how this mutation affected the nucleotidase activity of the NBD1‚NBD2 complex, analysis of the ATPase activity of the R2038W mutant protein alone and in complex with wild-type NBD1 was carried out. Login to comment
199 The affinity of interaction decreased under all conditions examined, as determined by comparison of the Kd values (Table Table 2: Modulation of ATPase Activities of NBD1‚NBD2 Complexes by Site-Specific Mutations NBD1‚NBD2 mutation domain NBD1‚NBD2 ATPasea (pmol/min) NBD1‚NBD2 ATPaseexptl (pmol/min) NBD1‚NBD2 ATPasecalcd b (pmol/min) motif/disease NBD1mut‚NBD2wt K969A, T970A NBD1 1.9 ( 0.4/5.3 ( 0.1 5.1 ( 0.1 7.2 synthetic NBD1wt‚NBD2mut K1978A, 1979A NBD2 3.1 ( 0.2/1.6 ( 0.3 1.5 ( 0.2 4.7 synthetic NBD1mut‚NBD2wt P940R NBD1 1.9 ( 0.3/5.2 ( 0.2 4.3 ( 0.1 7.1 AMD NBD1wt‚NBD2mut R2038W NBD2 3.1 ( 0.1/2.0 ( 0.2 4.4 ( 0.2 5.1 STGD NBD1wt‚NBD2wt wild type N/A 3.0 ( 0.3/5.4 ( 0.1 5.30 ( 0.3 8.4 none a Experimental ATPase activity corresponding to 6 pmol of the individual domains, NBD1 and NBD2, respectively. Login to comment
202 The ATPase assay was carried out as described under Experimental Procedures at 37 °C for 60 min. A theoretical curve is shown, indicating the results expected if the activity of NBD1‚NBD2 R2038W were additive (]) of that obtained for the individual domains. Each point represents the average of three independent experiments. 1). Login to comment
271 The only exception to this was with the NBD2 mutation R2038W, where mutation of this residue led to ATP hydrolysis of the complex that was nearly the sum of the individual NBDs, suggesting that Arg 2038 is critical to this inhibition. Login to comment

[hide] Mutation spectrum and founder chromosomes for the ... Invest Ophthalmol Vis Sci. 2004 Jun;45(6):1705-11. September AV, Vorster AA, Ramesar RS, Greenberg LJ
Mutation spectrum and founder chromosomes for the ABCA4 gene in South African patients with Stargardt disease.
Invest Ophthalmol Vis Sci. 2004 Jun;45(6):1705-11., [PMID:15161829]

Abstract [show]
PURPOSE: To assess the mutation spectrum of ABCA4 underlying Stargardt disease (STGD) in South Africa (SA) and to determine whether there is a single or a few founder chromosomes in SA STGD families. METHODS: Sixty-four probands exhibiting the STGD phenotype were screened for mutations in the 50 exons of ABCA4 by single-strand conformational polymorphism-heteroduplex analysis sequencing and restriction fragment length polymorphism analysis. Microsatellite marker haplotyping was used to determine the ancestry in 10 families. RESULTS: Fifty-seven ABCA4 disease-associated alleles were identified that comprised 16 different sequence variants, of which two were novel, in 40 individuals of the cohort of 64 subjects. The most common variants identified included the C1490Y, L2027F, R602W, V256splice, R152X, and 2588G-->C mutations. The C1490Y variant was the most common disease-associated variant identified (19/64 subjects) and was absent in 392 control chromosomes. At least 10 ABCA4 disease-associated haplotypes were identified. Two of these haplotypes, which carried the C1490Y mutation, were identified in three unrelated families. CONCLUSIONS: Results suggest that ABCA4 is the major gene underlying STGD in the cohort investigated. Five of the six common sequence variants identified were at a higher frequency in the SA cohort than reported in published data on individuals of similar ancestry. The mutation and haplotype data suggests that there are several ancestral haplotypes underlying STGD in SA. There seems to be at least two different origins for the common C1490Y mutation, as well as two for the R602W mutation, thereby suggesting several founder effects for STGD in SA.

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71 List of 16 Different Potential Disease-Associated Sequence Variants Identified in 64 SA Subjects with arSTGD Nucleotide Change Amino Acid Change Families (N ‫؍‬ 64) Exon Reference C454T R152X 4 5 3,33 G455A R152Q 1 5 35 C634T R212C 1 6 16,27 G768T (Splice donor) V256splice 5 6 15 C1885T R602W 6 13 9 2588G3C G863A 4 17 8 T3047C V989A 1 20 11 T4319C F1440S 1 29 9 G4328A* R1443H 1 29 This study G4469A C1490Y 19 30 15,9 G5077A V16931 1 36 36 C6079T L2027F 8 44 8 C6088A R2030X 1 44 9,37 C6112T R2038W 2 44 5 IVS45ϩ7G3A Splice donor 1 45 26 6352⌬A* Frameshift 1 46 This study No individuals positive for the R1443H variant were identified in 47 control individuals of Indian ancestry. Login to comment
125 AO (y) Phenotype Mutation 1 Mutation 2 224.1 9 STGD C1490Y R602W 170.2 10 STGD C1490Y R602W 241.1 9 STGD C1490Y 25883C 448.1 20 STGD C1490Y 2588G3C 113.3 10 STGD C1490Y L2027F 209.1 18 STGD C1490Y L2027F 165.4 10 STGD C1490Y V256splice 166.3 27 STGD C1490Y R152X 151.4 5 STGD C1490Y ND 219.1 5 (rapid clinical progression was observed by 9 years) STGD C1490Y ND 223.1 9 STGD C1490Y ND 307.1 9 STGD C1490Y ND 319.3 9 STGD C1490Y ND 385.1 10 STGD C1490Y ND 226.1 10 STGD C1490Y ND 142.2 10 STGD C1490Y ND 273.1 11 STGD C1490Y ND 382.1 12 STGD C1490Y ND 449.1 14 STGD C1490Y ND 344.2 ND STGD C1490Y ND 374.1 10 STGD L2027F 6352⌬A† 305.1 18 STGD L2027F R2038W 377.1 25 STGD L2027F R2038W 276.1 27 STGD L2027F R212C 204.4 8 STGD L2027F ND 135.4 13 STGD L2027F ND 446.1 9 STGD R602W ND 109.3 11 STGD R602W ND 110.7 13 STGD R602W ND 438.3 12 STGD R602W ND 123.1 9 STGD V256splice R152X 105.1* 10 STGD AND atypical RP V256splice R152X 24 129.3* 10 (rapid clinical progression was observed) STGD V256splice ND 163.22 10 STGD V256splice ND 173.1 8 STGD 2588G3C ND 9.4 27 STGD 2588G3C R152X 330.2 29 STGD R152Q V989A 372.1 31 STGD R1443H† R2030X 141.3 11 STGD F1440S IVS45ϩ7G3A (splice site mutation) 206.3 ND STGD V1693I ND Rows are arranged according to the age of onset (AO) starting with the earliest AO for the most common sequence variant. Login to comment

[hide] Functional analysis of genetic mutations in nucleo... Biochemistry. 2003 Sep 16;42(36):10683-96. Biswas-Fiss EE
Functional analysis of genetic mutations in nucleotide binding domain 2 of the human retina specific ABC transporter.
Biochemistry. 2003 Sep 16;42(36):10683-96., [PMID:12962493]

Abstract [show]
The rod outer segment (ROS) ABC transporter (ABCR) plays an important role in the outer segment of retinal rod cells, where it functions as a transporter of all-trans retinal, most probably as the complex lipid, retinylidene-phosphatidyl-ethanolamine. We report here a quantitative analysis of the structural and functional effects of genetic mutations, associated with several macular degenerations, in the second nucleotide-binding domain of ABCR (NBD2). We have analyzed the ATP binding, kinetics of ATP hydrolysis, and structural changes. The results of these multifaceted analyses were correlated with the disease severity and prognosis. Results presented here demonstrated that, in wild type NBD2, distinct conformational changes accompany nucleotide (ATP and ADP) binding. Upon ATP binding, NBD2 protein changed to a relaxed conformation where tryptophans became more solvent-exposed, while ADP binding reverses this process and leads back to a taut conformation that is also observed with the unbound protein. This sequence of conformational change appears to be important in the energetics of the ATP hydrolysis and may have important structural consequences in the ability of the NBD2 domain to act as a regulator of the nucleotide-binding domain 1. Some of the mutant proteins displayed strikingly different patterns of conformational changes upon nucleotide binding that pointed to unique structural consequences of these genetic mutations. The ABCR dysfunctions, associated with various retinopathies, are multifaceted in nature and include alterations in protein structure as well as the attenuation of ATPase activity and nucleotide binding.

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73 The NBD2 expression vector pET29aNBD2 was used as template, 12 cycles of PCR, and each cycle was 30 s at 95 °C, 30 s at 50 °C, and 15 min at 68°C using complimentary oligonucleotides to produce the mutations L1971R, R2038W, G2146D, K2175A, and D2177N. Login to comment
74 The primers used for mutagenesis were as follows: L1971R, CGC CCT GGA GAG TGC TTT GGC CTC CGG GGA GTG AAT GGT GCC GGC AAA AC; R2038W, CTT TAC CTT TAT GCC AGG CTT CGA GGT GTA CCA GC, G2146D, CTG GCC ATC ATG GTA AAG GAC GCC TTT CGA TGT AT; D2177N, ATC AAA TCC CCG AAG GAC AAC CTG CTT CCT GAC CTG AAC; K2175A, CA ATG AAG ATC AAA TCC CCG GCG GAC GAC CTG CTT CCT GA. All of the mutations were disease-associated with the exception of K2175A. Login to comment
103 The locations of the disease associated mutations investigated in this study; L1971R, R2038W, G2146D, L2027F, and D2177N are indicated. Login to comment
144 Here, we have used site-specific mutagenesis to create disease-related genetic mutations: L1971R, D2177N, L2027F, R2038W, and G2146D as well as a synthetic mutation, K2175A. Login to comment
153 Lane 1: protein molecular weight standards; lane 2, wild-type NBD2; lane 3, L2027F mutant; lane 4, L1971R mutant; lane 5, D2177N; lane 6, G2146D; lane 7, R2038W mutant; lane 8, K2175A. Login to comment
177 The mutation R2038W also led to a similar level of decrease in ATP hydrolysis relative to the wild-type control. Login to comment
179 The G2146D and R2038W mutations are associated with cone-rod dystrophy and Stargardt disease, respectively. These two degenerative syndromes are more severe than FFM or AMD, with respect to age of onset and time frame of disease progression. Login to comment
227 The binding constants for both G2146D and R2038W decreased as compared to the wild-type control (Figure 6C,D). Login to comment
228 The affinity for ATP was quite similar for both mutants; the G2146D Kd was 1.33 × 10-6 M while that of R2038W was 1.32 × 10-6 M (Table 1). Login to comment
253 The curves represent a least squares nonlinear regression curve fit of the data representing the (A) L1971R mutant, (B) D2177N mutant, (C) G2146D mutant, (D) R2038W mutant, and (E) K2175A mutant. Login to comment
267 Stern Volmer plots of the (A) wild-type NBD2, (B) L1971R mutant, (C) L2027F mutant, (D) D2177N mutant, (E) R2038W mutant, (F) G2146D mutant, and (F) K2175A mutant. Login to comment
282 The R2038W and G2146D quenching profiles (Figure 7E,F and Table 1) had notable differences when compared to that of the wild-type protein. Login to comment
286 For R2038W, the percent quenching was 30% for ATP bound versus 13% and 11% for the ADP and nucleotide-free forms. Login to comment
290 Clinically, the alteration of pattern of conformational change correlated well with the disease severity, since the mutations G2146D and R2038W are associated with STDG1 and CRD, which have an earlier age of onset and/or more rapid progression of disease. Login to comment
303 The mutation L1971R has been identified with individuals suffering from the milder form of macular degeneration, Fundus Flavimaculatus, while G2146D and R2038W are associated with STGD1 and CRD, both of which are more severe forms of degeneration. Login to comment
305 In this study, the mutations R2038W, L1971R and G2146D led to comparable (~50%) decreases in ATP hydrolysis relative to the wild-type control. Login to comment
353 The mutants R2038W and G2146D had comparable differences in nucleotide hydrolysis and thermodynamics of ATP binding. Login to comment
355 The R2038W mutant was conformationaly similar the wild-type protein as evidenced in the diminished quenching of tryptophan fluorescence (Table 1). Login to comment

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

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

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102 Thirty-Three Truncated and 98 Amino Acid-Changing Variants in the ABCA4 Gene Exon Nucleotide Change Effect (A) (B) AMD (n ‫؍‬ 182) Control (n ‫؍‬ 96) STGD (n ‫؍‬ 374) Allele Prevalence 2 106delT FS NS 0 0 1 Ͻ0.01 2 160 ϩ 1g 3 a Splice site NS 0 0 1 Ͻ0.01 3 161G 3 A Cys54Tyr NS 0 0 6 Ͻ0.01 3 179C 3 T Ala60Val NS 0 0 2 Ͻ0.01 3 194G 3 A Gly65Glu NS 0 0 2 Ͻ0.01 3 223T 3 G Cys75Gly NS 0 0 2 Ͻ0.01 3 247delCAAA FS NS 0 0 2 Ͻ0.01 3 298C 3 T Ser100Pro NS 0 0 1 Ͻ0.01 5 454C 3 T Arg152Stop NS 0 0 2 Ͻ0.01 6 574G 3 A Ala192Thr NS 0 0 1 Ͻ0.01 6 618C 3 G Ser206Arg NS 0 0 3 Ͻ0.01 6 634C 3 T Arg212Cys 0.02 Yes 0 0 7 0.01 6 635G 3 A Arg212His NS 2 2 6 0.01 6 658C 3 T Arg220Cys NS 0 0 2 Ͻ0.01 6 661delG FS NS 0 0 1 Ͻ0.01 666delAAAGACGGTGC 6 GC FS NS 0 0 1 Ͻ0.01 6 746A 3 C Asp249Gly NS 0 0 1 Ͻ0.01 8 899C 3 A Thr300Asn NS 0 0 1 Ͻ0.01 8 997C 3 T Arg333Trp NS 0 0 1 Ͻ0.01 9 1140T 3 A Asn380Lys NS 0 0 1 Ͻ0.01 9 1222C 3 T Arg408Stop NS 0 0 1 Ͻ0.01 10 1268A 3 G His423Arg NS 1 0 7 0.01 10 1335C 3 G Ser445Arg NS 0 0 1 Ͻ0.01 10 1344delG FS NS 0 0 1 Ͻ0.01 11 1411G 3 A Glu471Lys NS 0 0 3 Ͻ0.01 11 1513delATCAC FS NS 0 0 1 Ͻ0.01 12 1622T 3 C Leu541Pro 0.001 Yes 0 0 11 0.01 13 1804C 3 T Arg602Trp NS 0 0 3 Ͻ0.01 13 1805G 3 A Arg602Gln NS 0 0 1 Ͻ0.01 13 1819G 3 T Gly607Trp NS 0 0 1 Ͻ0.01 13 1823T 3 A Phe608Ile NS 0 0 1 Ͻ0.01 13 1927G 3 A Val643Met NS 0 0 1 Ͻ0.01 14 1989G 3 T Trp663Stop NS 0 0 1 Ͻ0.01 14 2005delAT FS NS 0 0 3 Ͻ0.01 14 2041C 3 T Arg681Stop NS 0 0 2 Ͻ0.01 14 2147C 3 T Thr716Met NS 0 0 1 Ͻ0.01 15 2291G 3 A Cys764Tyr NS 0 0 1 Ͻ0.01 15 2294G 3 A Ser765Asn NS 0 0 1 Ͻ0.01 15 2300T 3 A Val767Asp NS 0 0 2 Ͻ0.01 16 2385del16bp FS NS 0 0 1 Ͻ0.01 16 2453G 3 A Gly818Glu NS 0 0 1 Ͻ0.01 16 2461T 3 A Trp821Arg NS 0 0 1 Ͻ0.01 16 2546T 3 C Val849Ala NS 0 0 4 Ͻ0.01 16 2552G 3 A Gly851Asp NS 0 0 1 Ͻ0.01 16 2560G 3 A Ala854Thr NS 0 0 1 Ͻ0.01 17 2588G 3 C Gly863Ala 0.0006 No 2 2 28 0.02 17 2617T 3 C Phe873Leu NS 0 0 1 Ͻ0.01 18 2690C 3 T Thr897Ile NS 0 0 1 Ͻ0.01 18 2701A 3 G Thr901Ala NS 0 1 0 Ͻ0.01 18 2703A 3 G Thr901Arg NS 0 0 2 Ͻ0.01 19 2828G 3 A Arg943Gln NS 20 13 37 0.05 19 2883delC FS NS 0 0 1 Ͻ0.01 20 2894A 3 G Asn965Ser NS 0 0 3 Ͻ0.01 19 2912C 3 A Thr971Asn NS 0 0 1 Ͻ0.01 19 2915C 3 A Thr972Asn NS 0 0 1 Ͻ0.01 20 2920T 3 C Ser974Pro NS 0 0 1 Ͻ0.01 20 2966T 3 C Val989Ala NS 0 0 2 Ͻ0.01 20 2977del8bp FS NS 0 0 1 Ͻ0.01 20 3041T 3 G Leu1014Arg NS 0 0 1 Ͻ0.01 21 3055A 3 G Thr1019Ala NS 0 0 1 Ͻ0.01 21 3064G 3 A Glu1022Lys NS 0 0 1 Ͻ0.01 21 3091A 3 G Lys1031Glu NS 0 0 1 Ͻ0.01 21 3113G 3 T Ala1038Val 0.001 Yes 1 0 17 0.01 22 3205insAA FS NS 0 0 1 Ͻ0.01 22 3261G 3 A Glu1087Lys NS 0 0 2 Ͻ0.01 22 3322C 3 T Arg1108Cys 0.04 Yes 0 0 6 Ͻ0.01 22 3323G 3 A Arg1108His NS 0 0 1 Ͻ0.01 23 3364G 3 A Glu1122Lys NS 0 0 1 Ͻ0.01 (continues) Exon Nucleotide Change Effect (A) (B) AMD (n ‫؍‬ 182) Control (n ‫؍‬ 96) STGD (n ‫؍‬ 374) Allele Prevalence 23 3386G 3 T Arg1129Leu NS 0 0 3 Ͻ0.01 24 3531C 3 A Cys1158Stop NS 0 0 1 Ͻ0.01 25 3749T 3 C Leu1250Pro NS 0 0 1 Ͻ0.01 26 3835delGATTCT FS NS 0 0 1 Ͻ0.01 27 3940C 3 A Pro1314Thr NS 0 1 0 Ͻ0.01 28 4139C 3 T Pro1380Leu 0.001 Yes 0 0 10 0.01 28 4222T 3 C Trp1408Arg NS 0 0 2 Ͻ0.01 28 4223G 3 T Trp1408Leu NS 0 0 2 Ͻ0.01 28 4234C 3 T Gln1412stop NS 0 0 1 Ͻ0.01 29 4297G 3 A Val1433Ile NS 1 0 0 Ͻ0.01 29 4319T 3 C Phe1440Ser NS 0 0 1 Ͻ0.01 30 4353 - 1g 3 t Splice site NS 0 0 1 Ͻ0.01 30 4457C 3 T Pro1486Leu NS 0 0 1 Ͻ0.01 30 4462T 3 C Cys1488Arg NS 0 0 3 Ͻ0.01 30 4463G 3 T Cys1488Phe NS 0 0 2 Ͻ0.01 30 4469G 3 A Cys1490Tyr NS 0 0 3 Ͻ0.01 30 4531insC FS NS 0 0 2 Ͻ0.01 32 4538A 3 G Gln1513Arg NS 0 0 1 Ͻ0.01 30 4539 ϩ 1g 3 t Splice site NS 0 0 1 Ͻ0.01 31 4574T 3 C Leu1525Pro NS 0 0 1 Ͻ0.01 33 4733delGTTT FS NS 0 0 1 Ͻ0.01 4859delATAACAinsTCC 35 T FS NS 0 0 1 Ͻ0.01 36 4909G 3 A Ala1637Thr NS 0 0 1 Ͻ0.01 35 4918C 3 T Arg1640Trp NS 0 0 1 Ͻ0.01 35 4919G 3 A Arg1640Gln NS 0 0 1 Ͻ0.01 35 4954T 3 G Tyr1652Asp NS 0 0 1 Ͻ0.01 36 5077G 3 A Val1693Ile NS 0 0 1 Ͻ0.01 36 5186T 3 C Leu1729Pro NS 0 0 2 Ͻ0.01 36 5206T 3 C Ser1736Pro NS 0 0 1 Ͻ0.01 36 5212del11bp FS NS 0 0 1 Ͻ0.01 37 5225delTGGTGGTGGGC FS NS 0 0 1 Ͻ0.01 del LPA 37 5278del9bp 1760 NS 0 0 1 Ͻ0.01 37 5288delG FS NS 0 0 1 Ͻ0.01 38 5395A 3 G Asn1799Asp NS 0 0 1 Ͻ0.01 38 5451T 3 G Asp1817Glu NS 1 0 4 Ͻ0.01 39 5584 ϩ 5g 3 a Splice site 0.02 Yes 0 0 6 Ͻ0.01 40 5603A 3 T Asn1868Ile 0.0006 No 20 7 79 0.08 40 5651T 3 A Val1884GLu NS 0 0 1 Ͻ0.01 40 5657G 3 A Gly1886Glu NS 0 0 1 Ͻ0.01 40 5687T 3 A Val1896Asp NS 0 0 1 Ͻ0.01 40 5693G 3 A Arg1898His NS 0 0 1 Ͻ0.01 40 5714 ϩ 5g 3 a Splice site NS 0 0 1 Ͻ0.01 42 5843CA 3 TG Pro1948Leu NS 11 7 28 0.04 42 5882G 3 A Gly1961Glu Ͻ0.0001 Yes 1 0 43 0.03 43 5908C 3 T Leu1970Phe NS 1 0 1 Ͻ0.01 43 5917delG FS NS 0 0 1 Ͻ0.01 44 6079C 3 T Leu2027Phe 0.01 Yes 0 0 9 0.01 44 6088C 3 T Arg2030Stop NS 0 0 2 Ͻ0.01 44 6089G 3 A Arg2030Gln NS 0 0 1 Ͻ0.01 44 6112A 3 T Arg2038Trp NS 0 0 1 Ͻ0.01 45 6148A 3 C Val2050Leu NS 1 0 0 Ͻ0.01 46 6212A 3 T Tyr2071Phe NS 0 0 1 Ͻ0.01 45 6229C 3 T Arg2077Trp NS 0 0 2 Ͻ0.01 46 6320G 3 A Arg2107His 0.01 Yes 0 0 10 0.01 46 6383A 3 G His2128Arg NS 0 0 1 Ͻ0.01 47 6446G 3 T Arg2149Leu NS 0 0 1 Ͻ0.01 47 6449G 3 A Cys2150Tyr NS 0 0 5 Ͻ0.01 48 6529G 3 A Asp2177Asn NS 2 0 0 Ͻ0.01 48 6686T 3 C Leu2229Pro NS 0 0 1 Ͻ0.01 48 6707delTCACACAG FS NS 0 0 1 Ͻ0.01 48 6729 ϩ 1g 3 a Splice site NS 0 0 1 Ͻ0.01 49 6764G 3 T Ser2255Ile 0.009 No 16 4 54 0.06 49 6788G 3 T Arg2263Leu NS 0 0 1 Ͻ0.01 (A) The probability under the null hypothesis of similar prevalence of each variant in Stargardt (STGD) compared with non-STGD alleles (two-tailed Fisher`s exact test); (B) compatability of the variant existing in a ratio of 100:1 in STGD to control alleles, calculated using the binomial distribution. 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103 Thirty-Three Truncated and 98 Amino Acid-Changing Variants in the ABCA4 Gene Exon Nucleotide Change Effect (A) (B) AMD (n d1d; 182) Control (n d1d; 96) STGD (n d1d; 374) Allele Prevalence 2 106delT FS NS 0 0 1 b0d;0.01 2 160 af9; 1g 3 a Splice site NS 0 0 1 b0d;0.01 3 161G 3 A Cys54Tyr NS 0 0 6 b0d;0.01 3 179C 3 T Ala60Val NS 0 0 2 b0d;0.01 3 194G 3 A Gly65Glu NS 0 0 2 b0d;0.01 3 223T 3 G Cys75Gly NS 0 0 2 b0d;0.01 3 247delCAAA FS NS 0 0 2 b0d;0.01 3 298C 3 T Ser100Pro NS 0 0 1 b0d;0.01 5 454C 3 T Arg152Stop NS 0 0 2 b0d;0.01 6 574G 3 A Ala192Thr NS 0 0 1 b0d;0.01 6 618C 3 G Ser206Arg NS 0 0 3 b0d;0.01 6 634C 3 T Arg212Cys 0.02 Yes 0 0 7 0.01 6 635G 3 A Arg212His NS 2 2 6 0.01 6 658C 3 T Arg220Cys NS 0 0 2 b0d;0.01 6 661delG FS NS 0 0 1 b0d;0.01 666delAAAGACGGTGC 6 GC FS NS 0 0 1 b0d;0.01 6 746A 3 C Asp249Gly NS 0 0 1 b0d;0.01 8 899C 3 A Thr300Asn NS 0 0 1 b0d;0.01 8 997C 3 T Arg333Trp NS 0 0 1 b0d;0.01 9 1140T 3 A Asn380Lys NS 0 0 1 b0d;0.01 9 1222C 3 T Arg408Stop NS 0 0 1 b0d;0.01 10 1268A 3 G His423Arg NS 1 0 7 0.01 10 1335C 3 G Ser445Arg NS 0 0 1 b0d;0.01 10 1344delG FS NS 0 0 1 b0d;0.01 11 1411G 3 A Glu471Lys NS 0 0 3 b0d;0.01 11 1513delATCAC FS NS 0 0 1 b0d;0.01 12 1622T 3 C Leu541Pro 0.001 Yes 0 0 11 0.01 13 1804C 3 T Arg602Trp NS 0 0 3 b0d;0.01 13 1805G 3 A Arg602Gln NS 0 0 1 b0d;0.01 13 1819G 3 T Gly607Trp NS 0 0 1 b0d;0.01 13 1823T 3 A Phe608Ile NS 0 0 1 b0d;0.01 13 1927G 3 A Val643Met NS 0 0 1 b0d;0.01 14 1989G 3 T Trp663Stop NS 0 0 1 b0d;0.01 14 2005delAT FS NS 0 0 3 b0d;0.01 14 2041C 3 T Arg681Stop NS 0 0 2 b0d;0.01 14 2147C 3 T Thr716Met NS 0 0 1 b0d;0.01 15 2291G 3 A Cys764Tyr NS 0 0 1 b0d;0.01 15 2294G 3 A Ser765Asn NS 0 0 1 b0d;0.01 15 2300T 3 A Val767Asp NS 0 0 2 b0d;0.01 16 2385del16bp FS NS 0 0 1 b0d;0.01 16 2453G 3 A Gly818Glu NS 0 0 1 b0d;0.01 16 2461T 3 A Trp821Arg NS 0 0 1 b0d;0.01 16 2546T 3 C Val849Ala NS 0 0 4 b0d;0.01 16 2552G 3 A Gly851Asp NS 0 0 1 b0d;0.01 16 2560G 3 A Ala854Thr NS 0 0 1 b0d;0.01 17 2588G 3 C Gly863Ala 0.0006 No 2 2 28 0.02 17 2617T 3 C Phe873Leu NS 0 0 1 b0d;0.01 18 2690C 3 T Thr897Ile NS 0 0 1 b0d;0.01 18 2701A 3 G Thr901Ala NS 0 1 0 b0d;0.01 18 2703A 3 G Thr901Arg NS 0 0 2 b0d;0.01 19 2828G 3 A Arg943Gln NS 20 13 37 0.05 19 2883delC FS NS 0 0 1 b0d;0.01 20 2894A 3 G Asn965Ser NS 0 0 3 b0d;0.01 19 2912C 3 A Thr971Asn NS 0 0 1 b0d;0.01 19 2915C 3 A Thr972Asn NS 0 0 1 b0d;0.01 20 2920T 3 C Ser974Pro NS 0 0 1 b0d;0.01 20 2966T 3 C Val989Ala NS 0 0 2 b0d;0.01 20 2977del8bp FS NS 0 0 1 b0d;0.01 20 3041T 3 G Leu1014Arg NS 0 0 1 b0d;0.01 21 3055A 3 G Thr1019Ala NS 0 0 1 b0d;0.01 21 3064G 3 A Glu1022Lys NS 0 0 1 b0d;0.01 21 3091A 3 G Lys1031Glu NS 0 0 1 b0d;0.01 21 3113G 3 T Ala1038Val 0.001 Yes 1 0 17 0.01 22 3205insAA FS NS 0 0 1 b0d;0.01 22 3261G 3 A Glu1087Lys NS 0 0 2 b0d;0.01 22 3322C 3 T Arg1108Cys 0.04 Yes 0 0 6 b0d;0.01 22 3323G 3 A Arg1108His NS 0 0 1 b0d;0.01 23 3364G 3 A Glu1122Lys NS 0 0 1 b0d;0.01 (continues) Exon Nucleotide Change Effect (A) (B) AMD (n d1d; 182) Control (n d1d; 96) STGD (n d1d; 374) Allele Prevalence 23 3386G 3 T Arg1129Leu NS 0 0 3 b0d;0.01 24 3531C 3 A Cys1158Stop NS 0 0 1 b0d;0.01 25 3749T 3 C Leu1250Pro NS 0 0 1 b0d;0.01 26 3835delGATTCT FS NS 0 0 1 b0d;0.01 27 3940C 3 A Pro1314Thr NS 0 1 0 b0d;0.01 28 4139C 3 T Pro1380Leu 0.001 Yes 0 0 10 0.01 28 4222T 3 C Trp1408Arg NS 0 0 2 b0d;0.01 28 4223G 3 T Trp1408Leu NS 0 0 2 b0d;0.01 28 4234C 3 T Gln1412stop NS 0 0 1 b0d;0.01 29 4297G 3 A Val1433Ile NS 1 0 0 b0d;0.01 29 4319T 3 C Phe1440Ser NS 0 0 1 b0d;0.01 30 4353 afa; 1g 3 t Splice site NS 0 0 1 b0d;0.01 30 4457C 3 T Pro1486Leu NS 0 0 1 b0d;0.01 30 4462T 3 C Cys1488Arg NS 0 0 3 b0d;0.01 30 4463G 3 T Cys1488Phe NS 0 0 2 b0d;0.01 30 4469G 3 A Cys1490Tyr NS 0 0 3 b0d;0.01 30 4531insC FS NS 0 0 2 b0d;0.01 32 4538A 3 G Gln1513Arg NS 0 0 1 b0d;0.01 30 4539 af9; 1g 3 t Splice site NS 0 0 1 b0d;0.01 31 4574T 3 C Leu1525Pro NS 0 0 1 b0d;0.01 33 4733delGTTT FS NS 0 0 1 b0d;0.01 4859delATAACAinsTCC 35 T FS NS 0 0 1 b0d;0.01 36 4909G 3 A Ala1637Thr NS 0 0 1 b0d;0.01 35 4918C 3 T Arg1640Trp NS 0 0 1 b0d;0.01 35 4919G 3 A Arg1640Gln NS 0 0 1 b0d;0.01 35 4954T 3 G Tyr1652Asp NS 0 0 1 b0d;0.01 36 5077G 3 A Val1693Ile NS 0 0 1 b0d;0.01 36 5186T 3 C Leu1729Pro NS 0 0 2 b0d;0.01 36 5206T 3 C Ser1736Pro NS 0 0 1 b0d;0.01 36 5212del11bp FS NS 0 0 1 b0d;0.01 37 5225delTGGTGGTGGGC FS NS 0 0 1 b0d;0.01 del LPA 37 5278del9bp 1760 NS 0 0 1 b0d;0.01 37 5288delG FS NS 0 0 1 b0d;0.01 38 5395A 3 G Asn1799Asp NS 0 0 1 b0d;0.01 38 5451T 3 G Asp1817Glu NS 1 0 4 b0d;0.01 39 5584 af9; 5g 3 a Splice site 0.02 Yes 0 0 6 b0d;0.01 40 5603A 3 T Asn1868Ile 0.0006 No 20 7 79 0.08 40 5651T 3 A Val1884GLu NS 0 0 1 b0d;0.01 40 5657G 3 A Gly1886Glu NS 0 0 1 b0d;0.01 40 5687T 3 A Val1896Asp NS 0 0 1 b0d;0.01 40 5693G 3 A Arg1898His NS 0 0 1 b0d;0.01 40 5714 af9; 5g 3 a Splice site NS 0 0 1 b0d;0.01 42 5843CA 3 TG Pro1948Leu NS 11 7 28 0.04 42 5882G 3 A Gly1961Glu b0d;0.0001 Yes 1 0 43 0.03 43 5908C 3 T Leu1970Phe NS 1 0 1 b0d;0.01 43 5917delG FS NS 0 0 1 b0d;0.01 44 6079C 3 T Leu2027Phe 0.01 Yes 0 0 9 0.01 44 6088C 3 T Arg2030Stop NS 0 0 2 b0d;0.01 44 6089G 3 A Arg2030Gln NS 0 0 1 b0d;0.01 44 6112A 3 T Arg2038Trp NS 0 0 1 b0d;0.01 45 6148A 3 C Val2050Leu NS 1 0 0 b0d;0.01 46 6212A 3 T Tyr2071Phe NS 0 0 1 b0d;0.01 45 6229C 3 T Arg2077Trp NS 0 0 2 b0d;0.01 46 6320G 3 A Arg2107His 0.01 Yes 0 0 10 0.01 46 6383A 3 G His2128Arg NS 0 0 1 b0d;0.01 47 6446G 3 T Arg2149Leu NS 0 0 1 b0d;0.01 47 6449G 3 A Cys2150Tyr NS 0 0 5 b0d;0.01 48 6529G 3 A Asp2177Asn NS 2 0 0 b0d;0.01 48 6686T 3 C Leu2229Pro NS 0 0 1 b0d;0.01 48 6707delTCACACAG FS NS 0 0 1 b0d;0.01 48 6729 af9; 1g 3 a Splice site NS 0 0 1 b0d;0.01 49 6764G 3 T Ser2255Ile 0.009 No 16 4 54 0.06 49 6788G 3 T Arg2263Leu NS 0 0 1 b0d;0.01 (A) The probability under the null hypothesis of similar prevalence of each variant in Stargardt (STGD) compared with non-STGD alleles (two-tailed Fisher`s exact test); (B) compatability of the variant existing in a ratio of 100:1 in STGD to control alleles, calculated using the binomial distribution. 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[hide] 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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111 To compare this observation directly with our previous report (Lewis et al. 1999), we replaced five mutations (A1038V, L2027F, R2030Q, R2038W, V2050L) to linker regions. Login to comment

[hide] Molecular genetic analysis of ABCR gene in Japanes... Jpn J Ophthalmol. 2000 May-Jun;44(3):245-9. Fuse N, Suzuki T, Wada Y, Yoshida M, Shimura M, Abe T, Nakazawa M, Tamai M
Molecular genetic analysis of ABCR gene in Japanese dry form age-related macular degeneration.
Jpn J Ophthalmol. 2000 May-Jun;44(3):245-9., [PMID:10913642]

Abstract [show]
PURPOSE: To explore whether the mutation in the retina-specific ATP-binding cassette transporter (ABCR) gene, the Stargardt's disease gene, contributes to the prevalence of the dry form of age-related macular degeneration (dry AMD) in Japanese unrelated patients. METHODS: Twenty-five Japanese unrelated patients with dry AMD who were diagnosed by fluorescein angiography and indocyanine green angiography were chosen as the dry AMD group. None of these cases had apparent choroidal neovascularization. To detect the mutations in the ABCR gene, genomic DNA was extracted from leukocytes of peripheral blood, and 26 exons of the ABCR gene were amplified by polymerase chain reaction (PCR). All the PCR products were then directly sequenced. When a mutation was detected, the occurrence of a mutation was compared between these AMD patients and the control group. RESULTS: After direct sequencing, a point mutation in exon 29 was found in one of the 25 dry AMD patients. In addition, a polymorphism in exon 45 was found in two other patients, and three sequence variations in exon 23 were detected in all patients. The incidence in AMD patients in whom a mutation in exon 29 (4%) was detected was less than that in controls (5%). Screening of the intron-exon boundaries also led to the identification of intronic mutation in intron 33. CONCLUSION: In this study we found no relationship between allelic variation in the ABCR gene and the prevalence of dry AMD in Japanese unrelated patients.

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31 Mutations Found in ABCR* Gene in 26 Exons Examined in This Study Exon AMD† Stargardt`s Disease Exon AMD Stargardt`s Disease 11 E471K 29 T1428M 15 31 R1517S 16 G818E, G863A (D847H) 33 I1562T G1578R 17 34 N1614FS 18 35 19 V931M, 2884delC N965M, (R943Q) 36 5196ϩ1G→A 5041deL15 5196ϩ2T→C 20 40 R1898H R1898H 21 A1028V 42 G1961E G1961E 22 3211insGT, V1072A E1087K 43 L1970F 6006ϩ1G→T 23 R1129L 44 L2027F, R2038W (I2023I) 24 45 V2050L, R2077W (I2083I) 25 46 R2106C (V2094V) 27 48 6519⌬11bp D2177N 6568⌬C 6519⌬11bp 6709insG *ABCR: ATP-binding cassette transporter. Login to comment

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

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

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

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

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

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76 2 0071GrA R24H 1 19 2894ArG N965S 3 36 5196ϩ1GrA Splice 2 3 0161GrA C54Y 1 21 3113CrT A1038V 16 5196ϩ2TrC Splice 1 0179CrT A60V 1 22 3211insGT FS 1 37 5281del9 PAL1761del 1 0203CrG P68R 1 3212CrT S1071L 1 38 5459GrC R1820P 1 0223TrG C75G 1 3215TrC V1072A 1 39 5512CrT H1838Y 1 6 0634CrT R212C 1 3259GrA E1087K 1 5527CrT R1843W 1 0664del13 FS 1 3322CrT R1108C 6 40 5585-1GrA Splice 1 0746ArG D249G 1 23 3364GrA E1122K 1 5657GrA G1886E 1 8 1007CrG S336C 1 3385GrT R1129C 1 5693GrA R1898H 4 1018TrG Y340D 1 3386GrT R1129L 2 5714ϩ5GrA Splice 8 11 1411GrA E471K 1 24 3602TrG L1201R 1 42 5882GrA G1961E 16 12 1569TrG D523E 1 25 3610GrA D1204N 1 5898ϩ1GrT Splice 3 1622TrC L541P 1 28 4139CrT P1380L 4 43 5908CrT L1970F 1 1715GrA R572Q 2 4216CrT H1406Y 1 5929GrA G1977S 1 1715GrC R572P 1 4222TrC W1408R 4 6005ϩ1GrT Splice 1 13 1804CrT R602W 1 4232insTATG FS 1 44 6079CrT L2027F 11 1822TrA F608I 2 4253ϩ5GrT Splice 1 6088CrT R2030X 1 1917CrA Y639X 1 29 4297GrA V1433I 1 6089GrA R2030Q 1 1933GrA D645N 1 4316GrA G1439D 2 6112CrT R2038W 1 14 2005delAT FS 1 4319TrC F1440S 1 45 6148GrC V2050L 2 2090GrA W697X 1 4346GrA W1449X 1 6166ArT K2056X 1 2160ϩ1GrC Splice 1 30a 4462TrC C1488R 2 6229CrT R2077W 1 16 2453GrA G818E 1 4457CrT P1486L 1 46 6286GrA E2096K 1 2461TrA W821R 1 30b 4469GrA C1490Y 3 6316CrT R2106C 1 2536GrC D846H 1 4539ϩ1GrT Splice 1 47 6391GrA E2131K 1 2552GrC G851D 1 31 4577CrT T1526M 7 6415CrT R2139W 1 17 2588GrC G863A 11 4594GrA D1532N 3 6445CrT R2149X 1 19 2791GrA V931M 2 35 4947delC FS 1 48 6543del36 1181del12 1 2827CrT R943W 1 36 5041del15 VVAIC1681del 2 6709insG FS 1 2884delC FS 1 5087GrA S1696N 1 NOTE.-FS ϭ frameshift. Login to comment
77 2 0071GrA R24H 1 19 2894ArG N965S 3 36 5196af9;1GrA Splice 2 3 0161GrA C54Y 1 21 3113CrT A1038V 16 5196af9;2TrC Splice 1 0179CrT A60V 1 22 3211insGT FS 1 37 5281del9 PAL1761del 1 0203CrG P68R 1 3212CrT S1071L 1 38 5459GrC R1820P 1 0223TrG C75G 1 3215TrC V1072A 1 39 5512CrT H1838Y 1 6 0634CrT R212C 1 3259GrA E1087K 1 5527CrT R1843W 1 0664del13 FS 1 3322CrT R1108C 6 40 5585afa;1GrA Splice 1 0746ArG D249G 1 23 3364GrA E1122K 1 5657GrA G1886E 1 8 1007CrG S336C 1 3385GrT R1129C 1 5693GrA R1898H 4 1018TrG Y340D 1 3386GrT R1129L 2 5714af9;5GrA Splice 8 11 1411GrA E471K 1 24 3602TrG L1201R 1 42 5882GrA G1961E 16 12 1569TrG D523E 1 25 3610GrA D1204N 1 5898af9;1GrT Splice 3 1622TrC L541P 1 28 4139CrT P1380L 4 43 5908CrT L1970F 1 1715GrA R572Q 2 4216CrT H1406Y 1 5929GrA G1977S 1 1715GrC R572P 1 4222TrC W1408R 4 6005af9;1GrT Splice 1 13 1804CrT R602W 1 4232insTATG FS 1 44 6079CrT L2027F 11 1822TrA F608I 2 4253af9;5GrT Splice 1 6088CrT R2030X 1 1917CrA Y639X 1 29 4297GrA V1433I 1 6089GrA R2030Q 1 1933GrA D645N 1 4316GrA G1439D 2 6112CrT R2038W 1 14 2005delAT FS 1 4319TrC F1440S 1 45 6148GrC V2050L 2 2090GrA W697X 1 4346GrA W1449X 1 6166ArT K2056X 1 2160af9;1GrC Splice 1 30a 4462TrC C1488R 2 6229CrT R2077W 1 16 2453GrA G818E 1 4457CrT P1486L 1 46 6286GrA E2096K 1 2461TrA W821R 1 30b 4469GrA C1490Y 3 6316CrT R2106C 1 2536GrC D846H 1 4539af9;1GrT Splice 1 47 6391GrA E2131K 1 2552GrC G851D 1 31 4577CrT T1526M 7 6415CrT R2139W 1 17 2588GrC G863A 11 4594GrA D1532N 3 6445CrT R2149X 1 19 2791GrA V931M 2 35 4947delC FS 1 48 6543del36 1181del12 1 2827CrT R943W 1 36 5041del15 VVAIC1681del 2 6709insG FS 1 2884delC FS 1 5087GrA S1696N 1 NOTE.-FS afd; frameshift. Login to comment

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

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

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130 Among these four reported mutations, p.A1773V in ABCA4 was reported as one of the founder mutations (up to17%) in Latin American population [18]; p.R2038W mutation in USA, Estonia and South African population; p.R602W mutation in USA, South African population [2,3,19]; G607R in the German population[20]. Login to comment
131 Taken together, this study confirmed that these four mutations are pathogenic mutations and among these four reported mutations, p.A1773V, p.R2038W and p.R602W may have higher allele frequencies since they were frequently reported in different populations. Login to comment
132 We observed two mutations (p.R2038W and p.G607R) [1,2], which Figure 5. Login to comment
156 Allele frequency Family Gene Identified Mutations (Exon) Reported or novel SIFT PolyPhen PANTHER 1000G ESP6500 In-house A ABCA4 c.5318C.T;p.A1773V (Exon 38) Reported D $ PD $ T $ 0 0 0 c.4128+1 G.T (Exon 27) Novel N/A N/A N/A 0 0 0 B ABCA4 c.6112C.T; p.R2038W (Exon 44) Reported D $ PD $ De $ 0 0.00008 0 c.1804C.T; p. R602W (Exon 13) Reported D $ Benign De $ 0 0 0 C ABCA4 c.1819G.A;p.G607R(Exon 13, Homo*) Reported D $ PD $ De $ 0 0.000077 0 D ABCA4 c.6095A.G; p.H2032R (Exon 44) Novel D $ PD $ De $ 0 0 0 c.3420C.G;p.C1140W (Exon 23) Novel D $ PD $ De $ 0 0 0 E PROM1 c.730C.T; p.R244X (Exon 6) Novel N/A N/A N/A 0 0 0 c.1983+1 C.T (Exon18) Novel N/A N/A N/A 0 0 0 $ D: Damaging; PD, Possibly damaging; T, Tolerated; DE,Deleterious; N/A, No Answer; *Homo, Homozygous mutation; , SIFT (http://sift.jcvi.org/); PolyPhen (http://genetics.bwh.harvard.edu/pph2/). Login to comment