13-20189332-C-T

Position:

• chr13-20189332-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The ENST00000382848.5(GJB2):​c.250G>A​(p.Val84Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,806 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V84L) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GJB2 ENST00000382848.5 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:11
• Conservation: PhyloP100: 7.86

Genes affected

GJB2 (HGNC:4284): (gap junction protein beta 2) This gene encodes a member of the gap junction protein family. The gap junctions were first characterized by electron microscopy as regionally specialized structures on plasma membranes of contacting adherent cells. These structures were shown to consist of cell-to-cell channels that facilitate the transfer of ions and small molecules between cells. The gap junction proteins, also known as connexins, purified from fractions of enriched gap junctions from different tissues differ. According to sequence similarities at the nucleotide and amino acid levels, the gap junction proteins are divided into two categories, alpha and beta. Mutations in this gene are responsible for as much as 50% of pre-lingual, recessive deafness. [provided by RefSeq, Oct 2008]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 8 uncertain in ENST00000382848.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-20189332-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 17032.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 13-20189332-C-T is Pathogenic according to our data. Variant chr13-20189332-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 17036.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GJB2	NM_004004.6	c.250G>A	p.Val84Met	missense_variant	2/2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.250G>A	p.Val84Met	missense_variant	2/2		XP_011533351.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5	c.250G>A	p.Val84Met	missense_variant	2/2	1	NM_004004.6	ENSP00000372299	P1
GJB2	ENST00000382844.2	c.250G>A	p.Val84Met	missense_variant	1/1			ENSP00000372295	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251338 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135856

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.0000992

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461806 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727212

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

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: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:11

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:4

Pathogenic, no assertion criteria provided	literature only	OMIM	Nov 01, 2007	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, no assertion criteria provided	clinical testing	Counsyl	Jun 08, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Integrating Genomics into Medicine, Frazer Institute, University Of Queensland	Jun 02, 2023	- -

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	May 19, 2023	Published functional studies demonstrate a damaging effect with the variant resulting in gap junctions that are incapable of intercellular coupling (Matos et al., 2007); Not observed at a significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 19101659, 25266519, 12865758, 25388846, 16222667, 24774219, 23668481, 9529365, 31160754, 30344259, 34440441, 34652575, 36100214, 26553399, 17660464, 31992338, 32067424) -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Aug 21, 2023	The frequency of this variant in the general population is consistent with pathogenicity (http://gnomad.broadinstitute.org). This variant has been identified in at least one individual with hearing loss. Assessment of experimental evidence suggests this variant results in abnormal protein function. (PMID: 17660464) In multiple individuals, this variant has been seen with a single recessive pathogenic variant in the same gene, suggesting this variant may also be pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 25, 2024	This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 84 of the GJB2 protein (p.Val84Met). This variant is present in population databases (rs104894409, gnomAD 0.01%). This missense change has been observed in individuals with autosomal recessive non-syndromic deafness (PMID: 30344259, 31160754). ClinVar contains an entry for this variant (Variation ID: 17036). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GJB2 protein function with a positive predictive value of 95%. This variant disrupts the p.Val84 amino acid residue in GJB2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11556849, 12172394, 16380907, 19235794). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Progressive sensorineural hearing impairment Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Jan 01, 2017

- -

Autosomal dominant nonsyndromic hearing loss 3A Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Jun 08, 2016

- -

GJB2-related disorder Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jun 21, 2023

The GJB2 c.250G>A variant is predicted to result in the amino acid substitution p.Val84Met. This variant has been reported in the homozygous and compound heterozygous states in patients with nonsyndromic hearing loss (Plevova. 2018. PubMed ID: 30344259; Pandya. 2020. PubMed ID: 32067424; Table S2, Shen. 2019. PubMed ID: 31160754; Zhang. 2011. PubMed ID: 21366436; Cheng. 2005. PubMed ID: 16222667; Martínez-Saucedo. 2015. PubMed ID: 26553399; Primignani. 2009. PubMed ID: 19371219; Loeza-Becerra. 2014. PubMed ID: 24774219). This variant is reported in 0.0099% of alleles in individuals of Ashkenazi Jewish descent in gnomAD (http://gnomad.broadinstitute.org/variant/13-20763471-C-T). This variant is interpreted as pathogenic. -

Rare genetic deafness Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Feb 12, 2007

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	26
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.94	D;D;D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.99	.;.;D
M_CAP	Pathogenic	0.70	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.6	H;H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-3.0	D;D;.
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;.
Polyphen		1.0	D;D;D
Vest4		0.93
MutPred		0.97		Loss of glycosylation at S85 (P = 0.1298);Loss of glycosylation at S85 (P = 0.1298);Loss of glycosylation at S85 (P = 0.1298);
MVP		0.98
MPC		0.28
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.84
gMVP		0.95

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

Publications

LitVar

Other links and lift over

dbSNP: rs104894409; hg19: chr13-20763471;