rs587783646

Positions:

• chr13-20188948-AAC-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Strong PP5_Very_Strong

The NM_004004.6(GJB2):​c.632_633del​(p.Cys211LeufsTer5) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000958 in 1,461,562 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000096 (0 hom.)
• Consequence: GJB2 NM_004004.6 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 0.988

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 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 4 pathogenic variants in the truncated region.
• PP5: Variant 13-20188948-AAC-A is Pathogenic according to our data. Variant chr13-20188948-AAC-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 158608.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GJB2	NM_004004.6	c.632_633del	p.Cys211LeufsTer5	frameshift_variant	2/2	ENST00000382848.5
GJB2	XM_011535049.3	c.632_633del	p.Cys211LeufsTer5	frameshift_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GJB2	ENST00000382848.5	c.632_633del	p.Cys211LeufsTer5	frameshift_variant	2/2	1	NM_004004.6	P1
GJB2	ENST00000382844.2	c.632_633del	p.Cys211LeufsTer5	frameshift_variant	1/1			P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 250240 Hom.: 0 AF XY: 0.00000738 AC XY: 1 AN XY: 135508

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: 0.00000885

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000958 AC: 14 AN: 1461562 Hom.: 0 AF XY: 0.00000688 AC XY: 5 AN XY: 727076

Gnomad4 AFR exome AF: 0.0000299

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: 0.0000117

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 19, 2021	Published functional studies demonstrate this variant impairs gap junction functions (Xiao et al., 2011); Frameshift variant predicted to result in protein truncation, as the last 16 amino acids are replaced with 4 different amino acids, and other loss-of-function variants have been reported downstream in the Human Gene Mutation Database (Stenson et al., 2014); Not observed at a significant frequency in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 20863150, 17666888, 10049954, 9529365, 12910486) -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Dec 06, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Oct 05, 2023	This sequence change creates a premature translational stop signal (p.Cys211Leufs*5) in the GJB2 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 16 amino acid(s) of the GJB2 protein. This variant is present in population databases (rs587783646, gnomAD 0.0009%). This premature translational stop signal has been observed in individual(s) with autosomal recessive deafness (PMID: 9529365, 12910486). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as 631–632del. ClinVar contains an entry for this variant (Variation ID: 158608). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this premature translational stop signal affects GJB2 function (PMID: 20863150). For these reasons, this variant has been classified as Pathogenic. -

Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:2

Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Likely pathogenic, criteria provided, single submitter	literature only	Counsyl	Dec 17, 2014	- -

Hearing impairment Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Feb 08, 2013

- -

GJB2-related disorder Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 04, 2023

The GJB2 c.632_633delGT variant is predicted to result in a frameshift and premature protein termination (p.Cys211Leufs*5). This variant was reported as pathogenic for autosomal recessive hearing loss (Kelley. 1998. PubMed ID: 9529365; Xiao. 2010. PubMed ID: 20863150). This variant is reported in 0.00089% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/13-20763087-AAC-A). Frameshift variants in GJB2 are expected to be pathogenic. This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

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: rs587783646; hg19: chr13-20763087;