chr13-20189019-T-C

Variant names:

• chr13-20189019-T-C
• rs1131691709
• NM_004004.6:c.563A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM3_Strong PP3 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_004004.6(GJB2):c.563A>G variant in GJB2 is a missense variant predicted to cause substitution of lysine by arginine at amino acid 188 (p.Lys188Arg). The highest population minor allele frequency of the variant is 0.00025% (3/1180000) in the European (non-Finnish) population in gnomAD v.4.0.0 (PM2_Supporting). This variant has been reported in at least three probands with hearing loss (2.5 PM3_Strong points). Two probands were compound heterozygous (one confirmed trans, the other one assumed trans) with the pathogenic c.35delG, p.G12Vfs variant (Clinvar ID: 17004, PMID 17666888, internal data from GeneDx). Another proband was compound heterozygous for the pathogenic variant p.Leu90Pro (ClinVar ID: 17016, University of Minnesota internal data). The REVEL computational prediction analysis tool produced a score of 0.9 meeting PP3. In summary, this variant meets criteria to be classified as likely pathogenic for autosomal recessive hearing loss based on the ACMG/AMP criteria applied as specified by the Hearing Loss Expert Panel: PM2_Supporting, PM3_Strong, PP3 (VCEP specifications version 2; 01.17.2024). LINK:https://erepo.genome.network/evrepo/ui/classification/CA387460893/MONDO:0019497/005

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: GJB2 NM_004004.6 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:4
• Conservation: PhyloP100: 7.97
• Publications: 5 publications found

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 Gene-Disease associations (from GenCC):

• Bart-Pumphrey syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
• ichthyosis, hystrix-like, with hearing loss

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
• keratoderma hereditarium mutilans

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, G2P
• palmoplantar keratoderma-deafness syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, G2P
• autosomal recessive nonsyndromic hearing loss 1A

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, G2P, PanelApp Australia
• hearing loss, autosomal recessive

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• autosomal dominant keratitis-ichthyosis-hearing loss syndrome

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics
• autosomal dominant nonsyndromic hearing loss 3A

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• autosomal dominant nonsyndromic hearing loss

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• KID syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000296095 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6	c.563A>G	p.Lys188Arg	missense_variant	Exon 2 of 2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.563A>G	p.Lys188Arg	missense_variant	Exon 2 of 2		XP_011533351.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5	c.563A>G	p.Lys188Arg	missense_variant	Exon 2 of 2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.563A>G	p.Lys188Arg	missense_variant	Exon 1 of 1	6		ENSP00000372295.1
ENSG00000296095	ENST00000736390.1	n.232-3439A>G		intron_variant	Intron 1 of 3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152200 Hom.: 0 Cov.: 33

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461806 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727204

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53380

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111964

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152200 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74364

African (AFR) AF: 0.00 AC: 0 AN: 41430

American (AMR) AF: 0.00 AC: 0 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68036

Other (OTH) AF: 0.00 AC: 0 AN: 2090

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:2

Oct 26, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces lysine, which is basic and polar, with arginine, which is basic and polar, at codon 188 of the GJB2 protein (p.Lys188Arg). This variant is present in population databases (no rsID available, gnomAD 0.007%). This missense change has been observed in individual(s) with autosomal recessive nonsyndromic sensorineural deafness (PMID: 17666888; external communication). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 429984). 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%. Experimental studies have shown that this missense change affects GJB2 function (PMID: 23967136). For these reasons, this variant has been classified as Pathogenic. -

Apr 24, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The K188R variant in the GJB2 gene has been reported previously in association with autosomal recessive nonsyndromic sensorineural hearing loss (Putcha et al., 2007). The K188R variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The K188R variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. However, this substitution occurs at a position that is conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. Additionally, missense variants in nearby residues (R184G, R184W, R184Q, R184P, T186M, T186K, V190D) have been reported in the Human Gene Mutation Database in association with hearing loss (Stenson et al., 2014), supporting the functional importance of this region of the protein. We interpret K188R as a pathogenic variant. -

Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:1

Jun 25, 2025

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: GJB2 c.563A>G (p.Lys188Arg) results in a conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. The variant was absent in 251354 control chromosomes.c.563A>G has been observed in compound heterozygous individuals affected with Autosomal Recessive Non-Syndromic Hearing Loss (Putcha_2007, LCG internal data and external communication). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in mis-trafficking of the mutant protein (Ambrosi_2013). The following publications have been ascertained in the context of this evaluation (PMID: 17666888, 23967136, 25388846). ClinVar contains an entry for this variant (Variation ID: 429984). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Nonsyndromic genetic hearing loss Pathogenic:1

Mar 28, 2024

ClinGen Hearing Loss Variant Curation Expert Panel

Significance: Likely pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The NM_004004.6(GJB2):c.563A>G variant in GJB2 is a missense variant predicted to cause substitution of lysine by arginine at amino acid 188 (p.Lys188Arg). The highest population minor allele frequency of the variant is 0.00025% (3/1180000) in the European (non-Finnish) population in gnomAD v.4.0.0 (PM2_Supporting). This variant has been reported in at least three probands with hearing loss (2.5 PM3_Strong points). Two probands were compound heterozygous (one confirmed trans, the other one assumed trans) with the pathogenic c.35delG, p.G12Vfs variant (Clinvar ID: 17004, PMID 17666888, internal data from GeneDx). Another proband was compound heterozygous for the pathogenic variant p.Leu90Pro (ClinVar ID: 17016, University of Minnesota internal data). The REVEL computational prediction analysis tool produced a score of 0.9 meeting PP3. In summary, this variant meets criteria to be classified as likely pathogenic for autosomal recessive hearing loss based on the ACMG/AMP criteria applied as specified by the Hearing Loss Expert Panel: PM2_Supporting, PM3_Strong, PP3 (VCEP specifications version 2; 01.17.2024). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.88
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.94	D;D;D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	1.0	.;.;D
M_CAP	Pathogenic	0.67	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.2	H;H;H
PhyloP100		8.0
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-2.9	D;D;.
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0010	D;D;.
Polyphen		1.0	D;D;D
Vest4		0.98
MutPred		0.86		Loss of methylation at K188 (P = 0.0053);Loss of methylation at K188 (P = 0.0053);Loss of methylation at K188 (P = 0.0053);
MVP		0.99
MPC		0.26
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.95
gMVP		0.99
Mutation Taster		=1/99	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1131691709; hg19: chr13-20763158;