13-20189137-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM1BP4

The NM_004004.6(GJB2):c.445G>A(p.Ala149Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000052 in 1,613,980 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000052 ( 0 hom. )

Consequence

GJB2
NM_004004.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts P:1U:8

Conservation

PhyloP100: 2.10

Variant links:

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]

GJB2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PM1

In a chain Gap junction beta-2 protein (size 225) in uniprot entity CXB2_HUMAN there are 70 pathogenic changes around while only 16 benign (81%) in NM_004004.6

BP4

Computational evidence support a benign effect (MetaRNN=0.30752504).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6 link	c.445G>A	p.Ala149Thr	missense_variant	Exon 2 of 2	ENST00000382848.5	NP_003995.2	P29033H9U1J4
GJB2	XM_011535049.3 link	c.445G>A	p.Ala149Thr	missense_variant	Exon 2 of 2		XP_011533351.1	P29033H9U1J4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5 link	c.445G>A	p.Ala149Thr	missense_variant	Exon 2 of 2	1	NM_004004.6	ENSP00000372299.4		P29033
GJB2	ENST00000382844.2 link	c.445G>A	p.Ala149Thr	missense_variant	Exon 1 of 1	6		ENSP00000372295.1		P29033

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152200

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.000118

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000558

AC:

AN:

251006

Hom.:

AF XY:

0.0000442

AC XY:

AN XY:

135730

show subpopulations

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:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000106

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000520

AC:

AN:

1461780

Hom.:

Cov.:

AF XY:

0.0000509

AC XY:

AN XY:

727176

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.0000188

Gnomad4 NFE exome

AF:

0.0000621

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000526

AC:

AN:

152200

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74340

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.000118

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000529

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.0000494

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1Uncertain:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Autosomal recessive nonsyndromic hearing loss 1A

Uncertain:4

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 09, 2017

Genomic Diagnostic Laboratory, Division of Genomic Diagnostics, Children's Hospital of Philadelphia

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 13, 2017

Counsyl

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 15, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not specified

Uncertain:2

Nov 15, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: GJB2 c.445G>A (p.Ala149Thr) results in a non-conservative amino acid change located in the Connexin, N-terminal domain (IPR013092) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 5.6e-05 in 251006 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in GJB2 causing Non-Syndromic Hearing Loss (5.6e-05 vs 0.00034), allowing no conclusion about variant significance. c.445G>A has been reported in the literature as a non-informative genotype (second allele not specified) or as a presumed compound heterozygous genotype in individuals reportedly affected with congenital/AR-Non-Syndromic Hearing Loss/Familial Hearing Impairment (example, Rabionet_2000, Toth_2001, Toth_2004, Hashemi_2012, Bliznets_2012, Garcia-Garcia_2020). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

May 22, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Ala149Thr variant in GJB2 has been identified in 6 probands with hearing los s and in 1/584 control chromosomes (Toth 2004, Rabionet 2000, Hashemi 2012, Bliz netz 2012, LMM unpublished data). Only one of these probands carried a second pa thogenic variant on the other allele of GJB2 (Toth 2003). Computational analyses (biochemical amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIF T) suggest that the variant may not impact the protein, though this information is not predictive enough to rule out pathogenicity. In summary, additional infor mation is needed to fully assess the variant's clinical significance. -

not provided

Uncertain:2

Oct 12, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 25388846, 10982180, 22567861, 30245029, 16125251, 30708180, 15146474, 36147510, 23073770, 26582918, 24077912) -

Oct 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 149 of the GJB2 protein (p.Ala149Thr). This variant is present in population databases (rs111033225, gnomAD 0.008%). This missense change has been observed in individual(s) with GJB2-related conditions (PMID: 10982180, 15146474, 23073770, 36147510). ClinVar contains an entry for this variant (Variation ID: 44751). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt GJB2 protein function with a negative predictive value of 95%. 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. -

Autosomal recessive nonsyndromic hearing loss 1A;C2675235:Autosomal recessive nonsyndromic hearing loss 1B

Pathogenic:1

Baylor Genetics

Significance: Likely pathogenic

Review Status: flagged submission

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.073

BayesDel_addAF

Uncertain

0.10

BayesDel_noAF

Uncertain

0.10

CADD

Benign

DANN

Benign

0.97

DEOGEN2

Uncertain

0.66

D;D;D

Eigen

Benign

-0.50

Eigen_PC

Benign

-0.46

FATHMM_MKL

Benign

0.52

LIST_S2

Benign

0.40

.;.;T

M_CAP

Benign

0.064

MetaRNN

Benign

0.31

T;T;T

MetaSVM

Uncertain

0.51

MutationAssessor

Benign

0.74

N;N;N

PrimateAI

Benign

0.34

PROVEAN

Benign

-1.4

N;N;.

REVEL

Uncertain

0.50

Sift

Benign

0.23

T;T;.

Sift4G

Benign

0.18

T;T;.

Polyphen

0.018

B;B;B

Vest4

0.15

MVP

0.69

MPC

0.044

ClinPred

0.073

GERP RS

5.5

Varity_R

0.29

gMVP

0.85

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over