Genetic Variant OCA2:c.1842+1G>A (chr15-27955157-C-T) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_000275.3(OCA2):c.1842+1G>A variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.000000687 in 1,455,254 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

OCA2
NM_000275.3 splice_donor, intron

Scores

Splicing: ADA: 0.9999

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 6.82

Publications

2 publications found

Variant links:

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]

OCA2 Gene-Disease associations (from GenCC):

oculocutaneous albinism type 2
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics, G2P, ClinGen

OCA2 links:

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ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000275.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	OCA2	NM_000275.3	MANE Select	c.1842+1G>A		splice_donor intron	N/A	NP_000266.2
	OCA2	NM_001300984.2		c.1770+1G>A		splice_donor intron	N/A	NP_001287913.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	OCA2	ENST00000354638.8	TSL:1 MANE Select	c.1842+1G>A		splice_donor intron	N/A	ENSP00000346659.3
	OCA2	ENST00000353809.9	TSL:1	c.1770+1G>A		splice_donor intron	N/A	ENSP00000261276.8

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.87e-7

AC:

AN:

1455254

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

724516

show subpopulations

African (AFR)

AF:

0.0000300

AC:

AN:

33336

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26110

East Asian (EAS)

AF:

0.00

AC:

AN:

39678

South Asian (SAS)

AF:

0.00

AC:

AN:

86116

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1105934

Other (OTH)

AF:

0.00

AC:

AN:

60180

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.28

CADD

Uncertain

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.88

FATHMM_MKL

Pathogenic

0.97

PhyloP100

6.8

GERP RS

5.5

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.99

Position offset: 1

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over