Common founder effects of hereditary hemochromatosis, Wilson´s disease, the long QT syndrome and autosomal recessive deafness caused by two novel mutations in the WHRN and TMC1 genes.
Identification of a novel frameshift mutation in the DFNB31/WHRN gene in a Tunisian consanguineous family with hereditary non-syndromic recessive hearing loss.
It has been demonstrated that mutations in deafness, autosomal recessive 31 (DFNB31), the gene encoding whirlin, is responsible for nonsyndromic hearing loss (NSHL; DFNB31) and Usher syndrome type II (USH2D).
Moreover, some individuals from the Palestinian family also harbored a novel heterozygous truncating variant (c.1267C>T/p.R423X) in the DFNB31 gene, which is involved in autosomal recessive nonsyndromic deafness type DFNB31 and Usher syndrome type II.
The aim of the study was to determine (1) the frequency and type of mutations in the coding region of the GJB2 gene (sequencing), (2) the frequency of splice site mutation IVS1 + 1G > A in the GJB2 gene (multiplex ligation-dependent probe amplification analysis), (3) possible copy number changes in the GJB2, GJB3, GJB6, and WFS1 genes (multiplex ligation-dependent probe amplification analysis), and (4) the frequency of del(GJB6-D13S1830) in the GJB6 gene in 58 unrelated patients with nonsyndromic hearing loss from Croatia.
Of the 23 probands, six had mutations in DFNA genes [WFS1 (n = 2), COCH, ACTG1, TMC1, and POU4F3] known to cause autosomal dominant nonsyndromic hearing loss.
The p.Gly831Ser variant may be a new member to the group of heterozygous WFS1 mutations that lead to HI, while the pathogenicity of the rare variant p.Gly674Arg remained unclear.
WFS1 is responsible for autosomal dominant nonsyndromic deafness 6/14/38 and is the most frequent genetic cause of low-frequency SNHL (LFSNHL); however, the exact prevalence of WFS1 mutations in LFSNHL is unknown.
By co-immunoprecipitation and in vitro binding assays, we establish that the usherin cytodomain can bind to whirlin and harmonin, two PDZ domain-containing proteins that are defective in genetic forms of isolated deafness and USH type I, respectively.