rs1555341931

Positions:

• chr13-20189253-TCC-TT

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The ENST00000382848.5(GJB2):​c.327_328delinsA​(p.Glu110ArgfsTer2) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. G109G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GJB2 ENST00000382848.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.19

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 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 102 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-20189254-CC-T is Pathogenic according to our data. Variant chr13-20189254-CC-T is described in ClinVar as [Pathogenic]. Clinvar id is 556762.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GJB2	NM_004004.6	c.327_328delinsA	p.Glu110ArgfsTer2	frameshift_variant	2/2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.327_328delinsA	p.Glu110ArgfsTer2	frameshift_variant	2/2		XP_011533351.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5	c.327_328delinsA	p.Glu110ArgfsTer2	frameshift_variant	2/2	1	NM_004004.6	ENSP00000372299	P1
GJB2	ENST00000382844.2	c.327_328delinsA	p.Glu110ArgfsTer2	frameshift_variant	1/1			ENSP00000372295	P1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Jul 17, 2023	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with both deafness and skin conditions (OMIM). Dominant negative is also a suggested mechanism (PMID: 28428247). (I) 0108 - This gene is associated with both recessive and dominant disease. The autosomal dominant diseases are commonly associated with pathogenic missense variants. The autosomal recessive disease is associated with bi-allelic loss-of-function variants and includes missense and protein truncating variants (NIH Genetics Home Reference, PMID: 12792423). (I) 0112 - The condition associated with this gene has incomplete penetrance (PMID:31160754). (I) 0204 - Variant is predicted to result in a truncated protein (premature termination codon is NOT located at least 54 nucleotides upstream of the final exon-exon junction) with at least 1/3 of the protein sequence affected. (SP) 0251 - This variant is heterozygous. (I) 0115 - Variants in this gene are known to have variable expressivity. Severity can range from mild to profound with intrafamilial variability also commonly seen. Commonly, truncating variants are associated to a more severe hearing loss (PMID: 20301449). (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0701 - Other protein truncating variants located downstream, therefore comparable to the one identified in this case, have very strong previous evidence for pathogenicity (DECIPHER). (SP) 0803 - This variant has limited previous evidence of pathogenicity in individuals with hearing impairment (ClinVar, PMID: 24224790). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Feb 23, 2018	- -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1555341931; hg19: chr13-20763393;