rs727504302

Variant names:

• chr13-20189343-T-C
• NM_004004.6:c.239A>G

Your query was ambiguous. Multiple possible variants found:

• chr13-20189343-T-C
• chr13-20189343-T-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_004004.6(GJB2):​c.239A>G​(p.Gln80Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q80K) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GJB2 NM_004004.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.97

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 10 ACMG points.

• PM1: In a helix (size 29) in uniprot entity CXB2_HUMAN there are 23 pathogenic changes around while only 1 benign (96%) in NM_004004.6
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6	c.239A>G	p.Gln80Arg	missense_variant	Exon 2 of 2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.239A>G	p.Gln80Arg	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.239A>G	p.Gln80Arg	missense_variant	Exon 2 of 2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.239A>G	p.Gln80Arg	missense_variant	Exon 1 of 1	6		ENSP00000372295.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

May 17, 2023

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.239A>G (p.Gln80Arg) results in a conservative amino acid change located in the connexin, N-terminal domain (IPR013092) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251406 control chromosomes (gnomAD). c.239A>G has been reported in the literature in the homozygous state in an individual affected with Non-Syndromic Hearing Loss and as an uninformative genotype (heterozygosity versus compound heterozygosity not specified) in at least one other affected individual (e.g. Uyguner_2003, Chen_2011, Xing_2013). 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. However, other variants affecting the same amino acid (i.e. pQ80H, p.Q80L, pQ80K, p.Q80P) have been reported in association with hearing loss in the literature (HGMD database), suggesting the Gln80 residue may be important for protein function. The following publications have been ascertained in the context of this evaluation (PMID: 21777984, 12791041, 27785406). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;D;D
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.98	.;.;D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.7	H;H;H
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-4.0	D;D;.
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;.
Polyphen		1.0	D;D;D
Vest4		0.95
MutPred		0.99		Gain of MoRF binding (P = 0.0922);Gain of MoRF binding (P = 0.0922);Gain of MoRF binding (P = 0.0922);
MVP		0.98
MPC		0.29
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.97
gMVP		1.0

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr13-20763482;