1-94000862-C-A

Position:

• chr1-94000862-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_000350.3(ABCA4):​c.6453G>T​(p.Met2151Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M2151L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: ABCA4 NM_000350.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 1.14

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 Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_000350.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.39284182).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ABCA4	NM_000350.3	c.6453G>T	p.Met2151Ile	missense_variant	47/50	ENST00000370225.4
ABCA4	XM_047416704.1	c.6231G>T	p.Met2077Ile	missense_variant	46/49

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ABCA4	ENST00000370225.4	c.6453G>T	p.Met2151Ile	missense_variant	47/50	1	NM_000350.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Age related macular degeneration 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Jan 01, 2016

This variant was classified as: Uncertain significance. -

Retinal disorder;C3665347:Visual impairment Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Feb 17, 2014

- -

Retinal dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Blueprint Genetics

Apr 04, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Uncertain	0.065	T
BayesDel_noAF	Benign	-0.14
CADD	Benign	21
DANN	Uncertain	0.98
DEOGEN2	Benign	0.18	T;T
Eigen	Benign	-0.30
Eigen_PC	Benign	-0.019
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Benign	0.023	T
MetaRNN	Benign	0.39	T;T
MetaSVM	Benign	-0.48	T
MutationAssessor	Benign	-1.6	.;N
MutationTaster	Benign	0.96	N;N;N
PrimateAI	Benign	0.45	T
PROVEAN	Benign	0.10	.;N
REVEL	Uncertain	0.30
Sift	Benign	0.032	.;D
Sift4G	Benign	0.13	T;T
Polyphen		0.0	.;B
Vest4		0.40
MutPred		0.47		.;Loss of methylation at R2149 (P = 0.0656);
MVP		0.78
MPC		0.093
ClinPred		0.71	D
GERP RS		4.9
Varity_R		0.20
gMVP		0.33

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: rs1057518954; hg19: chr1-94466418;