13-20189406-C-T

Position:

• chr13-20189406-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP3_Strong PP5_Moderate

The NM_004004.6(GJB2):​c.176G>A​(p.Gly59Asp) 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 Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: GJB2 NM_004004.6 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P: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 Pathogenic. Variant got 10 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, 0.996
• PP5: Variant 13-20189406-C-T is Pathogenic according to our data. Variant chr13-20189406-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 163520.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GJB2	NM_004004.6	c.176G>A	p.Gly59Asp	missense_variant	2/2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.176G>A	p.Gly59Asp	missense_variant	2/2		XP_011533351.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5	c.176G>A	p.Gly59Asp	missense_variant	2/2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.176G>A	p.Gly59Asp	missense_variant	1/1	6		ENSP00000372295.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Rare genetic deafness Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Oct 23, 2014

The p.Gly59Asp variant in GJB2 has not been reported in individuals with hearing loss or in large population studies. However, several missense variants at the same amino acid position (p.Gly59Ala, p.Gly59Val, p.Gly59Arg, p.Gly59Ser) have b een reported in individuals with sensorineural hearing loss with or without palm oplantar hyperkeratosis. These variants were observed to segregate in affected f amily members in several pedigrees in an autosomal dominant pattern (Heathcote 2 000, Toth 2004, Leonard 2005, Alexandrino 2005), and in one study the variant wa s confirmed to have occurred de novo (Leonard 2005). This information strongly s uggests that variants at this amino acid residue are not tolerated. In addition, computational prediction tools and conservation analysis suggest that the p.Gly 59Asp variant may impact the protein. In summary, although additional studies ar e required to fully establish its clinical significance, this variant is likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;D;D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.96	.;.;D
M_CAP	Pathogenic	0.61	D
MetaRNN	Pathogenic	1.0	D;D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	3.7	H;H;H
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-6.9	D;D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;.
Polyphen		1.0	D;D;D
Vest4		0.95
MutPred		0.95		Gain of solvent accessibility (P = 0.0133);Gain of solvent accessibility (P = 0.0133);Gain of solvent accessibility (P = 0.0133);
MVP		0.98
MPC		0.31
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.97
gMVP		0.98

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: rs104894404; hg19: chr13-20763545;