rs1555440003

chr15-27951844-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000275.3(OCA2):c.1891G>A(p.Gly631Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000248 in 1,613,920 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G631A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: OCA2 NM_000275.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.41

Genes affected

OCA2 (HGNC:8101): (OCA2 melanosomal transmembrane protein) This gene encodes the human homolog of the mouse p (pink-eyed dilution) gene. The encoded protein is believed to be an integral membrane protein involved in small molecule transport, specifically tyrosine, which is a precursor to melanin synthesis. It is involved in mammalian pigmentation, where it may control skin color variation and act as a determinant of brown or blue eye color. Mutations in this gene result in type 2 oculocutaneous albinism. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000275.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
OCA2	NM_000275.3	c.1891G>A	p.Gly631Arg	missense_variant	18/24	ENST00000354638.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
OCA2	ENST00000354638.8	c.1891G>A	p.Gly631Arg	missense_variant	18/24	1	NM_000275.3	P1
OCA2	ENST00000353809.9	c.1819G>A	p.Gly607Arg	missense_variant	17/23	1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152132 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: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461788 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727208

Gnomad4 AFR exome AF: 0.0000597

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: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152132 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74320

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: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Jan 18, 2017

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 13, 2022

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 631 of the OCA2 protein (p.Gly631Arg). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with OCA2-related conditions. ClinVar contains an entry for this variant (Variation ID: 436093). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
Cadd	Uncertain	24
Dann	Pathogenic	1.0
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.59
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	D;D
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	0.84	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Benign	0.44	T
PROVEAN	Uncertain	-3.0	D;D
REVEL	Pathogenic	0.87
Sift	Benign	0.14	T;T
Sift4G	Benign	0.28	T;T
Polyphen		0.94	P;P
Vest4		0.86
MutPred		0.91		.;Gain of methylation at G631 (P = 0.0053);
MVP		1.0
MPC		0.47
ClinPred		0.94	D
GERP RS		5.2
Varity_R		0.31
gMVP		0.89

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.080		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: rs1555440003; hg19: chr15-28196990;