NM_000350.3:c.2875A>G

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1PM5PP3_ModeratePP5

The NM_000350.3(ABCA4):c.2875A>G(p.Thr959Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000991 in 1,613,992 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. T959S) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

ABCA4
NM_000350.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:5U:6

Conservation

PhyloP100: 7.94

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

PM1

In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000350.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-94046961-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 99168.Status of the report is criteria_provided_single_submitter, 1 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.922

PP5

Variant 1-94046962-T-C is Pathogenic according to our data. Variant chr1-94046962-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 236095.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=4, Uncertain_significance=7, Pathogenic=1}. Variant chr1-94046962-T-C is described in Lovd as [Likely_pathogenic]. Variant chr1-94046962-T-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCA4	NM_000350.3 link	c.2875A>G	p.Thr959Ala	missense_variant	Exon 19 of 50	ENST00000370225.4	NP_000341.2	P78363Q6AI28
ABCA4	NM_001425324.1 link	c.2653A>G	p.Thr885Ala	missense_variant	Exon 18 of 49		NP_001412253.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCA4	ENST00000370225.4 link	c.2875A>G	p.Thr959Ala	missense_variant	Exon 19 of 50	1	NM_000350.3	ENSP00000359245.3		P78363
ABCA4	ENST00000649773.1 link	c.2653A>G	p.Thr885Ala	missense_variant	Exon 18 of 19			ENSP00000496882.1		A0A3B3IRV8

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152112

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000159

AC:

AN:

251358

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135838

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000352

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000752

AC:

AN:

1461880

Hom.:

Cov.:

AF XY:

0.00000963

AC XY:

AN XY:

727240

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000989

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152112

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74298

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000107

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:5Uncertain:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:1Uncertain:1

Sep 16, 2020

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 23096905, 26593885, 28118664, 27813578, 29178665, 31618812) -

Sep 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 959 of the ABCA4 protein (p.Thr959Ala). This variant is present in population databases (rs368846708, gnomAD 0.007%). This missense change has been observed in individual(s) with Stargardt disease (PMID: 23096905; internal data). ClinVar contains an entry for this variant (Variation ID: 236095). 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) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on ABCA4 protein function. This variant disrupts the p.Thr959 amino acid residue in ABCA4. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10958763, 24097981; internal data). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Severe early-childhood-onset retinal dystrophy

Pathogenic:1

Jan 01, 2016

Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Optic atrophy

Pathogenic:1

Jan 01, 2022

Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Severe early-childhood-onset retinal dystrophy;C1858806:Cone-rod dystrophy 3;C1866422:Retinitis pigmentosa 19;C3495438:Age related macular degeneration 2

Pathogenic:1

May 21, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Retinal dystrophy

Pathogenic:1

Jan 01, 2022

Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

- -

not specified

Uncertain:1

May 14, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ABCA4 c.2875A>G (p.Thr959Ala) results in a non-conservative amino acid change located in the ABC transporter-like, ATP-binding domain (IPR003439) of 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 1.6e-05 in 251358 control chromosomes. c.2875A>G has been reported in the literature in individuals affected with retinal dystrophy/Stargardt disease (e.g. Sciezynska_2016, PIccardi_2019, Holtan_2021). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 33258285, 31618812, 26593885). ClinVar contains an entry for this variant (Variation ID: 236095). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Stargardt Disease, Recessive

Uncertain:1

Jun 14, 2016

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.2875A>G (p.Thr959Ala) variant has been reported in one study in which it is found in a compound heterozygous state with a second missense variant in one individual with Stargardt disease (Oldani et al. 2012). Control data are unavailable for the p.Thr959Ala variant which is reported at a frequency of 0.00003 in the European (Non-Finnish) population of the Exome Aggregation Consortium. This frequency is based on two alleles only in a region of good coverage hence the variant is presumed to be rare. Oldani et al. (2012) note that the variant, which lies in the cytoplasmic domain of the protein, results in the substitution of a polar amino acid for a non-polar one and that the Thr959 residue is conserved at this position in vertebrates. The evidence for this variant is limited. The p.Thr959Ala variant is therefore classified as a variant of unknown significance, but suspicious for pathogenicity for Stargardt disease. -

Cone-Rod Dystrophy, Recessive

Uncertain:1

Jun 14, 2016

Illumina Laboratory Services, Illumina

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

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.55

BayesDel_addAF

Pathogenic

0.26

BayesDel_noAF

Pathogenic

0.44

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.91

D;.

Eigen

Pathogenic

0.77

Eigen_PC

Pathogenic

0.76

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

D;D

M_CAP

Pathogenic

0.71

MetaRNN

Pathogenic

0.92

D;D

MetaSVM

Pathogenic

0.92

MutationAssessor

Uncertain

2.5

M;.

PrimateAI

Uncertain

0.65

PROVEAN

Pathogenic

-4.5

D;.

REVEL

Pathogenic

0.96

Sift

Uncertain

0.0090

D;.

Sift4G

Uncertain

0.014

D;.

Polyphen

0.99

D;.

Vest4

0.93

MutPred

0.71

Gain of catalytic residue at T959 (P = 0.1784);.;

MVP

0.95

MPC

0.46

ClinPred

0.93

GERP RS

5.5

Varity_R

0.81

gMVP

0.88

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over