13-20189303-C-T
Variant summary
Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM5PP2PP3_StrongPP5_Very_Strong
The NM_004004.6(GJB2):c.279G>A(p.Met93Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000576 in 1,613,898 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M93R) has been classified as Uncertain significance.
Frequency
Consequence
NM_004004.6 missense
Scores
Clinical Significance
Conservation
Publications
- Bart-Pumphrey syndromeInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
- ichthyosis, hystrix-like, with hearing lossInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
- keratoderma hereditarium mutilansInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, G2P
- palmoplantar keratoderma-deafness syndromeInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, G2P
- autosomal recessive nonsyndromic hearing loss 1AInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, G2P, PanelApp Australia
- hearing loss, autosomal recessiveInheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
- autosomal dominant keratitis-ichthyosis-hearing loss syndromeInheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics
- autosomal dominant nonsyndromic hearing loss 3AInheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
- autosomal dominant nonsyndromic hearing lossInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- KID syndromeInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 17 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| GJB2 | ENST00000382848.5 | c.279G>A | p.Met93Ile | missense_variant | Exon 2 of 2 | 1 | NM_004004.6 | ENSP00000372299.4 | ||
| GJB2 | ENST00000382844.2 | c.279G>A | p.Met93Ile | missense_variant | Exon 1 of 1 | 6 | ENSP00000372295.1 | |||
| ENSG00000296095 | ENST00000736390.1 | n.232-3723G>A | intron_variant | Intron 1 of 3 |
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 152198Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000159 AC: 4AN: 251190 AF XY: 0.0000147 show subpopulations
GnomAD4 exome AF: 0.0000616 AC: 90AN: 1461700Hom.: 0 Cov.: 33 AF XY: 0.0000564 AC XY: 41AN XY: 727172 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000197 AC: 3AN: 152198Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2AN XY: 74358 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Pathogenic:3
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 18776652, 16380907, 14985372, 25616557, 17666888, 20497192, 20668687, 12172394, 25388846, 22592158, 22695344, 30708180, 24156272, 15666300, 36478599, 30245029, 28483220, 25555641, 25447126) -
This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 93 of the GJB2 protein (p.Met93Ile). This variant is present in population databases (rs397516871, gnomAD 0.004%). This missense change has been observed in individuals with autosomal recessive deafness (PMID: 12172394, 14985372). ClinVar contains an entry for this variant (Variation ID: 44733). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GJB2 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects GJB2 function (PMID: 22592158). This variant disrupts the p.Met93 amino acid residue in GJB2. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
The GJB2 c.279G>A; p.Met93Ile variant (rs397516871) is reported in the literature in multiple individuals affected with hearing loss often found with a second pathogenic variant (Cryns 2004, Naghavi 2008, Najmabadi 2005, Putcha 2007, Wu 2002). This variant is also reported in ClinVar (Variation ID: 44733). This variant is found in the non-Finnish European population with an allele frequency of 0.003% (3/113608 alleles) in the Genome Aggregation Database. The methionine at codon 93 is highly conserved, and computational analyses predict that this variant is deleterious (REVEL: 0.874). Based on available information, this variant is considered to be likely pathogenic. References: Cryns K et al. A genotype-phenotype correlation for GJB2 (connexin 26) deafness. J Med Genet. 2004 Mar;41(3):147-54. PMID: 14985372. Naghavi A et al. GJB2 mutations in Baluchi population. J Genet. 2008 Aug;87(2):195-7. PMID: 18776652. Najmabadi H et al. GJB2 mutations: passage through Iran. Am J Med Genet A. 2005 Mar 1;133A(2):132-7. PMID: 15666300. Putcha GV et al. A multicenter study of the frequency and distribution of GJB2 and GJB6 mutations in a large North American cohort. Genet Med. 2007 Jul;9(7):413-26. PMID: 17666888. Wu BL et al. Effectiveness of sequencing connexin 26 (GJB2) in cases of familial or sporadic childhood deafness referred for molecular diagnostic testing. Genet Med. 2002 Jul-Aug;4(4):279-88. PMID: 12172394. -
Autosomal recessive nonsyndromic hearing loss 1A Pathogenic:2
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. -
Variant summary: GJB2 c.279G>A (p.Met93Ile) results in a conservative amino acid change located in the Connexin, N-terminal domain (IPR013092) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 251190 control chromosomes. c.279G>A has been reported in the literature in individuals affected with Autosomal Recessive Non-Syndromic Hearing Loss (example, Wu_2002, Cryns_2004, Snoeckx_2005, Tsukada_2010). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Autosomal dominant keratitis-ichthyosis-hearing loss syndrome;C0265964:Mutilating keratoderma;C0266004:Knuckle pads, deafness AND leukonychia syndrome;C1835672:Palmoplantar keratoderma-deafness syndrome;C1844678:X-linked mixed hearing loss with perilymphatic gusher;C1865234:Ichthyosis, hystrix-like, with hearing loss;C2673759:Autosomal recessive nonsyndromic hearing loss 1A;C2675750:Autosomal dominant nonsyndromic hearing loss 3A Pathogenic:1
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Rare genetic deafness Pathogenic:1
The p.Met93Ile variant in GJB2 has been reported in at least 8 individuals with hearing loss including four compound heterozygotes with pathogenic variants in t rans (Wu 2002, Cryns 2004, Najmabadi 2005, Snoeckx 2005, Putcha 2007, Naghavi 20 08, Rodriguez-Paris 2010, Tsukada 2010, LMM data). (Wu 2002, Cryns 2004, Tsukada 2010). The hearing loss described in these four individuals ranged from mild t o moderately-severe (Wu 2002, Cryns 2004, Tsukada 2010, LMM data). This variant has also been identified in 4/126570 European chromosomes by the Genome Aggregat ion Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs397516871). Alth ough this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency for nonsyndromic hear ing loss. Computational prediction tools and conservation analysis suggest that the variant may impact the protein, though this information is not predictive en ough to determine pathogenicity. In summary, although additional studies are req uired to fully establish its clinical significance, the p.Met93Ile variant is li kely pathogenic based on compound heterozygosity in multiple affected individual s. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at