rs61748526

Positions:

• chr1-94111517-A-C
• chr1-94111517-A-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM5 PP3_Strong PP5_Moderate

The NM_000350.3(ABCA4):​c.223T>G​(p.Cys75Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000743 in 1,614,084 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 Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C75R) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: ABCA4 NM_000350.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2 O:1
• Conservation: PhyloP100: 9.16

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 uncertain in NM_000350.3
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-94111517-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1054759.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 1-94111517-A-C is Pathogenic according to our data. Variant chr1-94111517-A-C is described in ClinVar as [Pathogenic]. Clinvar id is 99122.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr1-94111517-A-C is described in Lovd as [Likely_pathogenic]. Variant chr1-94111517-A-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ABCA4	NM_000350.3	c.223T>G	p.Cys75Gly	missense_variant	3/50	ENST00000370225.4
ABCA4	XM_047416704.1	c.223T>G	p.Cys75Gly	missense_variant	3/49

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ABCA4	ENST00000370225.4	c.223T>G	p.Cys75Gly	missense_variant	3/50	1	NM_000350.3	P1
ABCA4	ENST00000649773.1	c.223T>G	p.Cys75Gly	missense_variant	3/19

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152240 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

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: 0.00

Gnomad OTH AF: 0.000478

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461844 Hom.: 0 Cov.: 34 AF XY: 0.00000550 AC XY: 4 AN XY: 727226

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: 0.00000899

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152240 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74382

Gnomad4 AFR AF: 0.0000241

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: 0.00

Gnomad4 OTH AF: 0.000478

Bravo AF: 0.00000756

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 29, 2024	This sequence change replaces cysteine, which is neutral and slightly polar, with glycine, which is neutral and non-polar, at codon 75 of the ABCA4 protein (p.Cys75Gly). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with ABCA4-related conditions (PMID: 9973280, 23982839, 30093795). ClinVar contains an entry for this variant (Variation ID: 99122). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae 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. -
not provided, no classification provided	literature only	Retina International	-	- -

Severe early-childhood-onset retinal dystrophy Pathogenic:1

Likely pathogenic, no assertion criteria provided

research

NIHR Bioresource Rare Diseases, University of Cambridge

Jan 01, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.90	D;.
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D;D
M_CAP	Pathogenic	0.67	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	3.0	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-10	D;.
REVEL	Pathogenic	0.91
Sift	Uncertain	0.010	D;.
Sift4G	Uncertain	0.0060	D;.
Polyphen		0.91	P;.
Vest4		0.98
MutPred		0.91		Loss of stability (P = 0.0404);Loss of stability (P = 0.0404);
MVP		0.97
MPC		0.52
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.93
gMVP		0.97

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

Other links and lift over

dbSNP: rs61748526; hg19: chr1-94577073;