13-20189443-C-T

Variant names:

• chr13-20189443-C-T
• rs104894398
• NM_004004.6:c.139G>A

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_004004.6(GJB2):​c.139G>A​(p.Glu47Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,126 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GJB2 NM_004004.6 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 7.85

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 Likely_pathogenic. Variant got 9 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
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant 13-20189443-C-T is Pathogenic according to our data. Variant chr13-20189443-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 1806861.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6	c.139G>A	p.Glu47Lys	missense_variant	Exon 2 of 2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.139G>A	p.Glu47Lys	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.139G>A	p.Glu47Lys	missense_variant	Exon 2 of 2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.139G>A	p.Glu47Lys	missense_variant	Exon 1 of 1	6		ENSP00000372295.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250772 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135532

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: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460126 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 726012

Gnomad4 AFR exome AF: 0.00

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1 Uncertain:1

Jun 15, 2021

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is statistically more frequent in affected individuals than in the general population and/or healthy controls. Assessment of experimental evidence suggests this variant results in abnormal protein function. Multiple studies in various cell types show that this variant prevents cell-to-cell junctions from functioning (PMID: 17146396, 26749107). -

Jul 20, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Experimental studies have shown that this missense change affects GJB2 function (PMID: 17146396, 26749107). 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. ClinVar contains an entry for this variant (Variation ID: 1806861). This missense change has been observed in individual(s) with clinical features of GJB2-related conditions (PMID: 11102979, 17666888, 19366456, 20234132, 21366436, 25493717). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 47 of the GJB2 protein (p.Glu47Lys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	26
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.95	D;D;D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.99	.;.;D
M_CAP	Pathogenic	0.72	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.7	H;H;H
PrimateAI	Uncertain	0.65	T
PROVEAN	Uncertain	-3.9	D;D;.
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0010	D;D;.
Sift4G	Pathogenic	0.0010	D;D;.
Polyphen		1.0	D;D;D
Vest4		0.97
MutPred		0.96		Gain of ubiquitination at E47 (P = 0.0162);Gain of ubiquitination at E47 (P = 0.0162);Gain of ubiquitination at E47 (P = 0.0162);
MVP		0.94
MPC		0.29
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.97
gMVP		0.99

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: rs104894398; hg19: chr13-20763582;