rs1555341931

Variant names:

• chr13-20189254-CC-T
• rs1555341931
• NM_004004.6:c.327_328delGGinsA

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PVS1 PM2 PP2 PP5_Moderate

The NM_004004.6(GJB2):​c.327_328delGGinsA​(p.Glu110ArgfsTer2) variant causes a frameshift, missense 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 NM_004004.6 frameshift, missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 1.19
• Publications: 0 publications found

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]

GJB2 Gene-Disease associations (from GenCC):

• Bart-Pumphrey syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
• ichthyosis, hystrix-like, with hearing loss

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
• keratoderma hereditarium mutilans

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, G2P
• palmoplantar keratoderma-deafness syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, G2P
• autosomal recessive nonsyndromic hearing loss 1A

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, G2P, PanelApp Australia
• hearing loss, autosomal recessive

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• autosomal dominant keratitis-ichthyosis-hearing loss syndrome

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics
• autosomal dominant nonsyndromic hearing loss 3A

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• autosomal dominant nonsyndromic hearing loss

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• KID syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000296095 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 13 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 103 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 111 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. Gene score misZ: -0.72044 (below the threshold of 3.09). Trascript score misZ: 0.4379 (below the threshold of 3.09). GenCC associations: The gene is linked to autosomal recessive nonsyndromic hearing loss 1A, ichthyosis, hystrix-like, with hearing loss, keratoderma hereditarium mutilans, hearing loss, autosomal recessive, Bart-Pumphrey syndrome, palmoplantar keratoderma-deafness syndrome, autosomal dominant keratitis-ichthyosis-hearing loss syndrome, autosomal dominant nonsyndromic hearing loss 3A, autosomal dominant nonsyndromic hearing loss, KID syndrome.
• PP5: Variant 13-20189254-CC-T is Pathogenic according to our data. Variant chr13-20189254-CC-T is described in ClinVar as Pathogenic. ClinVar VariationId is 556762.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJB2	NM_004004.6	c.327_328delGGinsA	p.Glu110ArgfsTer2	frameshift_variant, missense_variant	Exon 2 of 2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.327_328delGGinsA	p.Glu110ArgfsTer2	frameshift_variant, 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.327_328delGGinsA	p.Glu110ArgfsTer2	frameshift_variant, missense_variant	Exon 2 of 2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.327_328delGGinsA	p.Glu110ArgfsTer2	frameshift_variant, missense_variant	Exon 1 of 1	6		ENSP00000372295.1
ENSG00000296095	ENST00000736390.1	n.232-3675_232-3674delGGinsA		intron_variant	Intron 1 of 3

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, single submitter

Submissions by phenotype

Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:2

Feb 23, 2018

Counsyl

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Jul 17, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.2
Mutation Taster		=0/200	disease causing

Splicing

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

Other links and lift over

dbSNP: rs1555341931; hg19: chr13-20763393;