Monogenic hearing loss

Gene: GJB3

I don't know

Comment on list classification: Leaving rating as green for now, but with recommendation of review at the next GMS update.

Created: 12 Jan 2021, 10:14 p.m. | Last Modified: 12 Jan 2021, 10:14 p.m.

Panel Version: 2.145

GJB3 - nonsyndromic genetic deafness association DISPUTED in ClinGen.

A large number of early studies have looked at GJB3 variants in HL patients. In all cases targeted screening of hearing loss genes was performed, with only a few genes looked at in most cases. At least 17 protein altering variants have been reported, but with no or limited segregation data. Two variants (NM_001005752.1:c.94C>T, Arg32Trp and c.598G>A, Val200Ile) are found at high allele frequency in the general population (both >0.02 gnomad v3.1) and c.529T>G, Tyr177Asp at a fairly high frequency (0.005535). 14 other variants are either not present in gnomad, or found at low frequency (< 0.0005). There is some data to support a functional change in proteins with 5 of the variants but no animal knockout model has been reported. One variant ((Ile141Val) found in a compound het case (Lui et al 2000) was found to migrate in to the cell surface in a similar way to wild type protein.

Monoallelic cases:
PMID:9843210 - Xia et al. 1998 - report monallelic variants found in GJB3 in 2 families with sensorineural deafness. Only the GJB3 gene was sequenced. In both families some carriers were unaffected. The two variants are ENST00000373362.3:c.547G>A GLU183LYS, ENST00000373362.3:c.538C>T (ARG180TER).

PMID:12630965 - Mhatre et al. 2003 - assessed 63 individuals with non-syndromic sporadic hearing impairment for CX31 (GJB3) mutations. 15 out of 63 patients (24%) had variants but only one variant was protein altering (C94T, R32W). This was found in two unrelated individuals with late onset hearing loss.

PMID: 10790215 - López-Bigas et al 2000 - report the molecular analysis of GJB3 in 153 patients with deafness and 110 with peripheral neuropathy. Identified two amino acid changes in patients; R32W and V200I. However, the R32W change was also detected in 18% of control subjects.

PMID:12791041 - Uyguner et al. 2003; Screened 60 Turkish patients with autosomal‐recessive NSSHL for variants in GJB2, GJB3, GJA1, DeltaGJB6-D13S1830 and CLDN14. A novel heterozygous variant, C667A;P223T, in GJB3 was found in a family with two affected children. However, the non-affected father also carried this variant. The authors suggest they may carry a second non-identified variant in a functionally related gene.

PMID:15131355 - Alexandrino et al. 2004 - analysed the GJB3 gene in 67 families with sporadic nonsyndromic hearing impairment. They found three amino acid changes: Y177D (c.529T > G), 49delK (c.144-146delGAA), and R32W (c.1227C > T). Abstract only accessed.

PMID:17259707 - Yang et al. 2007 - screened 260 Taiwanese individuals with nonsyndromic deafness and 120 with normal hearing. 8 genes were looked at GJB2, GJE1, GJB6, GJB4, GJB3, GJB1, GJA1 and pseudogene rho GJA1. A novel variant was identified GJB3 in 3 patients with nonsyndromic deafness. Abstract only accessed.

PMID:19744334 - Yuan et al. 2009 - screened 284 unrelated school children with hearing loss, and 200 control patients for variants in GJB2, GJB3, GJB6, SLC26A4, 12S rRNA, and tRNAser(UCN) genes. 2 patients were found with heterozygous protein altering variants that were not found in controls; c.24_49ins26bp (results in frameshift), c.497A>G, N166S. However, the patient carrying N166S mutation in one allele was verified to carry GJB2 235delC mutation in the other. Parental DNA was not available for the patient with the c.24_49ins26bp variant.

PMID:22617145 - Oh et al. 2013 - looked at GJB3 and GJB6 in 215 unrelated Korean nonsyndromic sensorineural HL patients. 7 variants were identified in GJB3. 2 variants (c.79G>A,p.V27M and c.250G>A,p.V84I) were not observed in normal Korean controls. Functional tests showed that these two variants did not functional normally when each was expressed as a heterozygote with the wild-type Cx31.

PMID: 23638949 - Yao et al 2013 - screened 227 segregating deaf students and 200 individuals with normal hearing for variants in GJB2, GJB3, SLC26A4, and mtDNA m.C1494T and m.A1555G. Four patients carried three unclassified mutations in GJB3 genes. Abstract only accessed.

PMID:25214170 - Beck et al. 2015; screened 188 HL probands in a 3 step process with GJB2 first, then GJB1, GJB3 and GJB6 and then if tested negative or heterozygote, testing of GJA1, GJB4, SLC26A4 and PJVK. 3 amino acid changes, c.166A>C, Lys56Gln (2/188), c.302G>A, Arg101Gln (1/188) and c.317G>A, Arg106His (1/188) were detected in the patient cohort but not in controls. The authors report that the role of these sequence variations remains unclear as no second mutation was found to establish a causative connection between genotype and phenotype.

PMID: 27610647 - Chen et al 2016 - using NGS they screened GJB2, SLC26A4, and GJB3, as well as exons of 57 additional candidate genes in 116 Chinese Han individuals suffering from hearing loss. 2 heterozygous variants were detected in GJB3 - c.131G>C, p.Trp44Ser; c.580G>A, p.Ala194Thr.

Biallelic cases:
PMID: 10587579 - Liu et al. (2000) - screened 25 Chinese families with recessive deafness and identified in two families affected individuals who were compound heterozygotes for Cx31 mutations. Both families had an in-frame 3 bp deletion (423-425delATT) in one allele, which leads to the loss of an isoleucine residue at codon 141, and a 423A>G transversion in the other allele, which creates an Ile>Val substitution (I141V) (later found to function as wild type by He et al 2005). Note: I think coords should be NM_001005752.1:c.421A>G and NM_001005752.1:c.421_423del.

Functional studies:
PMID: 16077902 - He et al 2005 - functional analysis of 11 disease-associated Cx31 (GJB3) variants, 2 which are associated with dominant HL (R180X, E183K) and 2 recessive HL (I141V, 141delI). R180X, E183K and 141delI were characterised by cytoplasmic accumulation of Cx31 and the absence of cell surface expression. I141V migrates mainly to the cell surface, which resembles that of WT Cx31.

Created: 23 Dec 2020, 11:31 a.m. | Last Modified: 12 Jan 2021, 10:12 p.m.

Panel Version: 2.144

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Phenotypes
Deafness, autosomal dominant 2B OMIM:612644

Publications

• 9843210
• 12630965
• 10790215
• 12791041
• 15131355
• 17259707
• 19744334
• 22617145
• 23638949
• 25214170
• 27610647
• 10587579
• 16077902

Red List (low evidence)

Association with dominant deafness has been disputed as the variants originally reported are present at high frequency in the population. ClinGen assessed as DISPUTED.

Created: 2 Jan 2020, 4:25 a.m. | Last Modified: 2 Jan 2020, 4:25 a.m.

Panel Version: 2.4

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, maternally imprinted (paternal allele expressed)

Phenotypes
Deafness, autosomal dominant 2B, MIM#612644

Publications

• 9843210

Green List (high evidence)

Inheritance:Autosomal dominant;Autosomal recessive;Digenic dominant

Created: 9 Feb 2016, 10:04 a.m.

Mode of inheritance
Other

Phenotypes
#133200:Erythrokeratodermia variabilis et progressiva[Hyperkeratosis, generalizedLocalized symmetric fixed, yellow- or red-brown hyperkeratotic plaques (extensor surface of extremities, buttocks, and lateral trunk)Palmoplantar keratoderma, patchy (&gt; 50%)Transient, migratory sharply outlined erythema (in some patients)Darkening of periorificial areas; PapillomatosisAcanthosisHypergranulosisCompact orthohyperkeratosis with retained nucleiFollicular plugging in less affected areas; Enlarged porcelain-white lunulae]; #220290:Deafness, digenic, GJB2/GJB3[Hearing loss, sensorineural, prelingual profoundVestibular dysfunction (in some patients)]; #612644:Deafness, autosomal dominant 2B[Hearing loss, bilateral high-frequency, sensorineural]

Comment when marking as ready: Expert review and OMIM confirmed

Created: 29 Jan 2016, 3:28 p.m.

Comment on mode of inheritance: evidence from OMIM of some biallelic cases

Created: 29 Jan 2016, 3:28 p.m.