rs1553193813

Positions:

• chr1-94077747-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000350.3(ABCA4):​c.1497G>A​(p.Trp499*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ABCA4 NM_000350.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.52

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-94077747-C-T is Pathogenic according to our data. Variant chr1-94077747-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 438087.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-94077747-C-T is described in Lovd as [Pathogenic]. Variant chr1-94077747-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ABCA4	NM_000350.3	c.1497G>A	p.Trp499*	stop_gained	11/50	ENST00000370225.4	NP_000341.2
ABCA4	XM_047416704.1	c.1497G>A	p.Trp499*	stop_gained	11/49
LOC124904222	XR_007066231.1	n.203-5982C>T		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ABCA4	ENST00000370225.4	c.1497G>A	p.Trp499*	stop_gained	11/50	1	NM_000350.3	ENSP00000359245.3
ABCA4	ENST00000649773.1	c.1497G>A	p.Trp499*	stop_gained	11/19			ENSP00000496882.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 24, 2023	Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 32581362, 28041643) -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 25, 2020	For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in ABCA4 are known to be pathogenic (PMID: 10958761, 24938718, 25312043, 26780318). This variant has been observed in individual(s) with inherited retinal dystrophy (PMID: 28041643). ClinVar contains an entry for this variant (Variation ID: 438087). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Trp499*) in the ABCA4 gene. It is expected to result in an absent or disrupted protein product. -

Cone-rod dystrophy 3 Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Bioscientia Institut fuer Medizinische Diagnostik GmbH, Sonic Healthcare

Apr 20, 2017

- -

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
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	38
DANN	Uncertain	1.0
Eigen	Pathogenic	0.83
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.98	D
Vest4		0.90
GERP RS		5.2

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: rs1553193813; hg19: chr1-94543303;