rs770892393

chr16-21685228-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Moderate PM2 PP3_Moderate PP5_Moderate

The NM_144672.4(OTOA):c.268-2A>G variant causes a splice acceptor change. The variant allele was found at a frequency of 0.00000137 in 1,459,142 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. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: OTOA NM_144672.4 splice_acceptor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.38

Genes affected

OTOA (HGNC:16378): (otoancorin) The protein encoded by this gene is specifically expressed in the inner ear, and is located at the interface between the apical surface of the inner ear sensory epithelia and their overlying acellular gels. It is prposed that this protein is involved in the attachment of the inner ear acellular gels to the apical surface of the underlying nonsensory cells. Mutations in this gene are associated with autosomal recessive deafness type 22 (DFNB22). Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2009]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.019152047 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 16-21685228-A-G is Pathogenic according to our data. Variant chr16-21685228-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 505849.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
OTOA	NM_144672.4	c.268-2A>G		splice_acceptor_variant		ENST00000646100.2
OTOA	NM_001161683.2	c.31-2A>G		splice_acceptor_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
OTOA	ENST00000646100.2	c.268-2A>G		splice_acceptor_variant			NM_144672.4	P2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251104 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135742

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459142 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726000

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000253

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.01e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Rare genetic deafness Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

May 31, 2017

The c.268-2A>G variant in OTOA has not been previously reported in individuals w ith hearing loss, but has been identified in 1/111514 European chromosomes by th e Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP r s770892393). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. Th is variant occurs in the invariant region (+/- 1/2) of the splice consensus sequ ence and is predicted to cause altered splicing leading to an abnormal or absent protein. Loss of function of the OTOA gene is an established disease mechanism in autosomal recessive hearing loss. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive hearing loss based on the pr edicted impact of the variant. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Benign	-0.13
Cadd	Pathogenic	32
Dann	Benign	0.92
Eigen	Pathogenic	0.87
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Benign	0.24	N
MutationTaster	Benign	1.0	D;D;D
GERP RS		4.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.77
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.87		Position offset: 6
DS_AL_spliceai		1.0		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs770892393; hg19: chr16-21696549;