1-94014665-G-A

Position:

• chr1-94014665-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_000350.3(ABCA4):​c.5338C>T​(p.Pro1780Ser) variant causes a missense 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P1780A) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ABCA4 NM_000350.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 10.0

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a transmembrane_region Helical (size 20) in uniprot entity ABCA4_HUMAN there are 32 pathogenic changes around while only 0 benign (100%) in NM_000350.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-94014665-G-C is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.887

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ABCA4	NM_000350.3	c.5338C>T	p.Pro1780Ser	missense_variant	38/50	ENST00000370225.4	NP_000341.2
ABCA4	XM_047416704.1	c.5116C>T	p.Pro1706Ser	missense_variant	37/49		XP_047272660.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ABCA4	ENST00000370225.4	c.5338C>T	p.Pro1780Ser	missense_variant	38/50	1	NM_000350.3	ENSP00000359245	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.68
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.70	D;D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	1.0	D;D
M_CAP	Uncertain	0.20	D
MetaRNN	Pathogenic	0.89	D;D
MetaSVM	Pathogenic	0.81	D
MutationAssessor	Pathogenic	3.3	.;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-7.4	.;D
REVEL	Pathogenic	0.83
Sift	Uncertain	0.0020	.;D
Sift4G	Uncertain	0.032	D;D
Polyphen		1.0	.;D
Vest4		0.88
MutPred		0.56		.;Loss of glycosylation at S1782 (P = 0.1133);
MVP		0.98
MPC		0.47
ClinPred		1.0	D
GERP RS		4.7
Varity_R		0.85
gMVP		0.91

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.37		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.37		Position offset: -29

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs121909207; hg19: chr1-94480221;