rs138157885

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM5PP2PP5

The NM_000350.3(ABCA4):​c.1522C>T​(p.Arg508Cys) variant causes a missense change. The variant allele was found at a frequency of 0.000178 in 1,613,918 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R508P) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00019 ( 0 hom. )

Consequence

ABCA4
NM_000350.3 missense

Scores

2
12
5

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4U:4

Conservation

PhyloP100: 3.75

Publications

16 publications found
Variant links:
Genes affected
ABCA4 (HGNC:34): (ATP binding cassette subfamily A member 4) The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intracellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the ABC1 subfamily. Members of the ABC1 subfamily comprise the only major ABC subfamily found exclusively in multicellular eukaryotes. This protein is a retina-specific ABC transporter with N-retinylidene-PE as a substrate. It is expressed exclusively in retina photoreceptor cells, and the gene product mediates transport of an essental molecule, all-trans-retinal aldehyde (atRAL), across the photoreceptor cell membrane. Mutations in this gene are found in patients diagnosed with Stargardt disease, a form of juvenile-onset macular degeneration. Mutations in this gene are also associated with retinitis pigmentosa-19, cone-rod dystrophy type 3, early-onset severe retinal dystrophy, fundus flavimaculatus, and macular degeneration age-related 2. [provided by RefSeq, Sep 2019]
ABCA4 Gene-Disease associations (from GenCC):
  • ABCA4-related retinopathy
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
  • cone-rod dystrophy 3
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
  • severe early-childhood-onset retinal dystrophy
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Ambry Genetics
  • retinitis pigmentosa 19
    Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
  • cone-rod dystrophy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • retinitis pigmentosa
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • Stargardt disease
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM1
In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 11 uncertain in NM_000350.3
PM5
Other missense variant is known to change same aminoacid residue: Variant chr1-94077721-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3249758.Status of the report is criteria_provided_single_submitter, 1 stars.
PP2
Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 578 curated pathogenic missense variants (we use a threshold of 10). The gene has 28 curated benign missense variants. Gene score misZ: -0.65813 (below the threshold of 3.09). Trascript score misZ: 1.3628 (below the threshold of 3.09). GenCC associations: The gene is linked to cone-rod dystrophy 3, retinitis pigmentosa 19, ABCA4-related retinopathy, severe early-childhood-onset retinal dystrophy, cone-rod dystrophy, Stargardt disease, retinitis pigmentosa.
PP5
Variant 1-94077722-G-A is Pathogenic according to our data. Variant chr1-94077722-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 298258.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
ABCA4NM_000350.3 linkc.1522C>T p.Arg508Cys missense_variant Exon 11 of 50 ENST00000370225.4 NP_000341.2 P78363Q6AI28
ABCA4NM_001425324.1 linkc.1522C>T p.Arg508Cys missense_variant Exon 11 of 49 NP_001412253.1
LOC124904222XR_007066231.1 linkn.203-6007G>A intron_variant Intron 1 of 1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
ABCA4ENST00000370225.4 linkc.1522C>T p.Arg508Cys missense_variant Exon 11 of 50 1 NM_000350.3 ENSP00000359245.3 P78363
ABCA4ENST00000649773.1 linkc.1522C>T p.Arg508Cys missense_variant Exon 11 of 19 ENSP00000496882.1 A0A3B3IRV8

Frequencies

GnomAD3 genomes
AF:
0.000105
AC:
16
AN:
152164
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000483
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000654
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.000191
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000179
AC:
45
AN:
251082
AF XY:
0.000177
show subpopulations
Gnomad AFR exome
AF:
0.000123
Gnomad AMR exome
AF:
0.0000579
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.0000463
Gnomad NFE exome
AF:
0.000300
Gnomad OTH exome
AF:
0.000490
GnomAD4 exome
AF:
0.000185
AC:
271
AN:
1461636
Hom.:
0
Cov.:
31
AF XY:
0.000188
AC XY:
137
AN XY:
727060
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33476
American (AMR)
AF:
0.0000894
AC:
4
AN:
44718
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26118
East Asian (EAS)
AF:
0.0000504
AC:
2
AN:
39688
South Asian (SAS)
AF:
0.000104
AC:
9
AN:
86198
European-Finnish (FIN)
AF:
0.0000374
AC:
2
AN:
53418
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5762
European-Non Finnish (NFE)
AF:
0.000219
AC:
244
AN:
1111864
Other (OTH)
AF:
0.000149
AC:
9
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.478
Heterozygous variant carriers
0
17
33
50
66
83
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
10
20
30
40
50
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.000105
AC:
16
AN:
152282
Hom.:
0
Cov.:
32
AF XY:
0.000134
AC XY:
10
AN XY:
74464
show subpopulations
African (AFR)
AF:
0.0000481
AC:
2
AN:
41562
American (AMR)
AF:
0.0000653
AC:
1
AN:
15306
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5176
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4818
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10612
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.000191
AC:
13
AN:
68020
Other (OTH)
AF:
0.00
AC:
0
AN:
2114
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.516
Heterozygous variant carriers
0
2
3
5
6
8
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000205
Hom.:
0
Bravo
AF:
0.000106
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000465
AC:
4
ExAC
AF:
0.000189
AC:
23
EpiCase
AF:
0.000327
EpiControl
AF:
0.000593

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:4Uncertain:4
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Retinal dystrophy Pathogenic:1Uncertain:1
Feb 13, 2017
Blueprint Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 01, 2022
Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Pathogenic:1
Jan 19, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 508 of the ABCA4 protein (p.Arg508Cys). This variant is present in population databases (rs138157885, gnomAD 0.03%). This missense change has been observed in individual(s) with Stargardt disease (PMID: 26780318, 28559085). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 298258). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt ABCA4 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

Cone-rod dystrophy 3 Pathogenic:1
Dec 29, 2023
3billion
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.017%). Predicted Consequence/Location: Missense variant In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.66 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.78 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000298258 /PMID: 18024811). A different missense change at the same codon (p.Arg508Pro) has been reported to be associated with ABCA4 related disorder (PMID: 29555955). Therefore, this variant is classified as Likely pathogenic according to the recommendation of ACMG/AMP guideline. -

Retinitis pigmentosa Pathogenic:1
Jul 31, 2023
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: ABCA4 c.1522C>T (p.Arg508Cys) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00018 in 251082 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in ABCA4 causing Retinitis Pigmentosa (0.00018 vs 0.0014), allowing no conclusion about variant significance. c.1522C>T has been reported in the literature in multiple individuals affected with macular dystrophy (Michaelides_2007), autosomal recessive stargardt Disease (examples: Jiang_2015, Stone_2017, Hu_ABCA4_2019), cone-rod dystrophy (Jiang_2015, Falsini_2022), autosomal recessive retinitis pigmentosa (examples: Ma_2021, Neveling_2012). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 35260635, 31543898, 26780318, 33691693, 18024811, 22334370, 28559085). Four submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as VUS (n=2) and pathogenic/likely pathogenic (n=2). Based on the evidence outlined above, the variant was classified as pathogenic for autosomal recessive stargardt disease and retinitis pigmentosa. -

Retinitis Pigmentosa, Recessive Uncertain:1
Jun 14, 2016
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Severe early-childhood-onset retinal dystrophy Uncertain:1
May 31, 2021
DBGen Ocular Genomics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Macular degeneration Uncertain:1
Jun 14, 2016
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.1522C>T (p.Arg508Cys) variant has been reported in two studies and is found in a total of three patients with various phenotypes including one in a compound heterozygous state with Stargardt disease, one in a compound heterozygous state with cone-rod dystrophy and one with macular dystrophy without clear zygosity information (Michaelides et al. 2007; Jiang et al. 2016). The p.Arg508Cys variant was absent from 100 controls and is reported at a frequency of 0.00047 in the European American population of the Exome Sequencing Project. Based on the evidence, the p.Arg508Cys variant is classified as a variant of unknown significance but suspicious for pathogenicity for ABCA4-related disorders. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.12
BayesDel_addAF
Uncertain
0.080
D
BayesDel_noAF
Pathogenic
0.18
CADD
Uncertain
24
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.75
D;.
Eigen
Uncertain
0.46
Eigen_PC
Uncertain
0.45
FATHMM_MKL
Uncertain
0.95
D
LIST_S2
Uncertain
0.89
D;D
M_CAP
Uncertain
0.17
D
MetaRNN
Uncertain
0.47
T;T
MetaSVM
Uncertain
0.18
D
MutationAssessor
Benign
1.9
L;.
PhyloP100
3.8
PrimateAI
Benign
0.22
T
PROVEAN
Uncertain
-3.8
D;.
REVEL
Pathogenic
0.66
Sift
Benign
0.041
D;.
Sift4G
Uncertain
0.029
D;.
Polyphen
0.92
P;.
Vest4
0.71
MVP
0.96
MPC
0.32
ClinPred
0.20
T
GERP RS
4.3
Varity_R
0.20
gMVP
0.77
Mutation Taster
=9/91
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.0
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs138157885; hg19: chr1-94543278; COSMIC: COSV64676760; API