13-20188936-TA-T

Position:

• chr13-20188936-TA-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_004004.6(GJB2):​c.645delT​(p.Arg216fs) 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 Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: GJB2 NM_004004.6 frameshift
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 0.354

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 12 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. Fraction of 0.0529 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-20188936-TA-T is Pathogenic according to our data. Variant chr13-20188936-TA-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 449487.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.645delT	p.Arg216fs	frameshift_variant	2/2	ENST00000382848.5	NP_003995.2
GJB2	XM_011535049.3	c.645delT	p.Arg216fs	frameshift_variant	2/2		XP_011533351.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GJB2	ENST00000382848.5	c.645delT	p.Arg216fs	frameshift_variant	2/2	1	NM_004004.6	ENSP00000372299.4
GJB2	ENST00000382844.2	c.645delT	p.Arg216fs	frameshift_variant	1/1	6		ENSP00000372295.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Counsyl

Jan 03, 2017

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 30, 2017

The c.645delT variant in the GJB2 gene has been reported previously, using alternate nomenclature as c.644delT, along with the c.35delG variant in a pediatric patient with prelingual nonsyndromic sensorineural hearing loss, though it was unclear if the parents were tested to determine phase of the variants (Angeli et al., 2008; King et al., 2012). The c.645delT variant causes a frameshift starting with codon Arginine 216, changes this amino acid to an Aspartic acid residue, and creates a premature Stop codon at position 18 of the new reading frame, denoted p.Arg216AspfsX18. The c.645delT variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). We interpret c.645delT as a likely pathogenic variant. -

Rare genetic deafness Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jun 02, 2016

The p.Arg216AspfsExtX6 variant in GJB2 has been reported in 1 individual with no nsyndromic hearing loss (Angeli 2008), and was absent from large population stud ies. This variant is predicted to cause a frameshift, which alters the protein?s amino acid sequence beginning at position 216 and leads to a new termination co don 18 amino acids downstream, thus resulting in a longer protein (the abnormal protein is 6 amino acids longer than the normal protein). In summary, although a dditional studies are required to fully establish its clinical significance, thi s variant is likely pathogenic. -

Mutilating keratoderma;C0266004:Knuckle pads, deafness AND leukonychia syndrome;C1835672:Palmoplantar keratoderma-deafness syndrome;C1865234:Ichthyosis, hystrix-like, with hearing loss;C2673759:Autosomal recessive nonsyndromic hearing loss 1A;C2675750:Autosomal dominant nonsyndromic hearing loss 3A Other:1

not provided, no classification provided

phenotyping only

GenomeConnect - Brain Gene Registry

-

Variant interpreted as Likely pathogenic and reported on 07-18-2017 by Lab GeneDx. Assertions are reported exactly as they appear on the patient provided laboratory report. GenomeConnect does not attempt to reinterpret the variant. The IDDRC-CTSA National Brain Gene Registry (BGR) is a study funded by the U.S. National Center for Advancing Translational Sciences (NCATS) and includes 13 Intellectual and Developmental Disability Research Center (IDDRC) institutions. The study is led by Principal Investigator Dr. Philip Payne from Washington University. The BGR is a data commons of gene variants paired with subject clinical information. This database helps scientists learn more about genetic changes and their impact on the brain and behavior. Participation in the Brain Gene Registry requires participation in GenomeConnect. More information about the Brain Gene Registry can be found on the study website - https://braingeneregistry.wustl.edu/. -

Computational scores

Source: dbNSFP v4.3

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: rs1555341794; hg19: chr13-20763075;