rs61750644

Variant names:

• chr1-94001974-T-A
• rs61750644
• NM_000350.3:c.6166A>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000350.3(ABCA4):​c.6166A>T​(p.Lys2056*) variant causes a stop gained change involving the alteration of a non-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 Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. K2056K) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: ABCA4 NM_000350.3 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4 O:1
• Conservation: PhyloP100: 2.24
• Publications: 6 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 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 1-94001974-T-A is Pathogenic according to our data. Variant chr1-94001974-T-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 99432.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCA4	NM_000350.3	c.6166A>T	p.Lys2056*	stop_gained	Exon 45 of 50	ENST00000370225.4	NP_000341.2
ABCA4	NM_001425324.1	c.5944A>T	p.Lys1982*	stop_gained	Exon 44 of 49		NP_001412253.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCA4	ENST00000370225.4	c.6166A>T	p.Lys2056*	stop_gained	Exon 45 of 50	1	NM_000350.3	ENSP00000359245.3
ABCA4	ENST00000465352.1	n.582A>T		non_coding_transcript_exon_variant	Exon 6 of 6	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2 Other:1

Retina International

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

Oct 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Lys2056*) in the ABCA4 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ABCA4 are known to be pathogenic (PMID: 10958761, 24938718, 25312043, 26780318). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with Stargardt disease (PMID: 9973280, 28559085). ClinVar contains an entry for this variant (Variation ID: 99432). For these reasons, this variant has been classified as Pathogenic.

Oct 30, 2017

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Inborn genetic diseases Pathogenic:1

Jun 07, 2018

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Retinal dystrophy Pathogenic:1

Jun 25, 2019

Blueprint Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	49
DANN	Uncertain	0.99
DEOGEN2	Benign	0.0	.;.
Eigen	Pathogenic	0.71
Eigen_PC	Uncertain	0.55
LIST_S2	Benign	0.0	.;.
MetaRNN	Benign	0.0	.;.
MutationAssessor	Benign	0.0	.;.
PhyloP100		2.2
PROVEAN	Benign	0.0	.;.
Sift	Pathogenic	0.0	.;.
Sift4G	Pathogenic	0.0	.;.
Vest4		0.93
GERP RS		3.6
Mutation Taster		=0/200	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

Other links and lift over

dbSNP: rs61750644; hg19: chr1-94467530;