NM_004004.6:c.278T>C

Variant names:

• chr13-20189304-A-G
• rs1461894310
• NM_004004.6:c.278T>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_004004.6(GJB2):​c.278T>C​(p.Met93Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,738 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 Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: GJB2 NM_004004.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.27

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 8 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
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.971

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6	c.278T>C	p.Met93Thr	missense_variant	Exon 2 of 2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.278T>C	p.Met93Thr	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.278T>C	p.Met93Thr	missense_variant	Exon 2 of 2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.278T>C	p.Met93Thr	missense_variant	Exon 1 of 1	6		ENSP00000372295.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251230 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135792

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461738 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727184

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000468 Hom.: 0

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Aug 19, 2024

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.278T>C (p.Met93Thr) results in a non-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 allele was found at a frequency of 4e-06 in 251230 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.278T>C has been reported in the literature in the simple heterozygous state in at least 1 individual affected with Autosomal Recessive Non-Syndromic Hearing Loss (example, Putcha_2007), however this is an insufficient genotype for the reported inheritance pattern. These report(s) do not provide unequivocal conclusions about association of the variant with Autosomal Recessive Non-Syndromic Hearing Loss. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 17666888). ClinVar contains an entry for this variant (Variation ID: 551851). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Autosomal recessive nonsyndromic hearing loss 1A Uncertain:1

May 09, 2017

Counsyl

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.81
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.83	D;D;D
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.93	.;.;D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.97	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.5	M;M;M
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-5.4	D;D;.
REVEL	Pathogenic	0.95
Sift	Benign	0.042	D;D;.
Sift4G	Benign	0.070	T;T;.
Polyphen		1.0	D;D;D
Vest4		0.96
MutPred		0.87		Loss of stability (P = 0.0055);Loss of stability (P = 0.0055);Loss of stability (P = 0.0055);
MVP		0.88
MPC		0.30
ClinPred		0.98	D
GERP RS		5.3
Varity_R		0.87
gMVP		0.95

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: rs1461894310; hg19: chr13-20763443;