Heterozygous Deletion of Exon 8 in WFS1 Gene in Two Wolfram Syndrome Probands with Hearing Loss: Case Report

Abstract

Point mutations in the Wolfram syndrome 1 gene (WFS1) are attributed the autosomal dominant and/or recessive mild type sensorineural hearing loss in first degree relatives. Total genomic DNA was isolated from peripheral blood of affected probands and controls, Multiplex polymerase chain reaction was performed and followed by multiplex ligated probe amplification analysis. Sensorineural hearing loss was moderate in a 48-year-old male patient (case 1) and sensorineural hearing loss and optic atrophy were evident in his 16 year old daughter (case 2). We identified heterozygous deletion in exon 8 of WFS1 gene (Wolframin protein) in father and in one of his affected daughters with hearing loss and optic atrophy. The genetic results demonstrate the necessity of screening for the possible point mutation and/or larger deletions in WFS1 gene in cases with non-syndromic mild type sensorineural hearing loss. This study emphasizes the need for careful molecular evaluation in cases with impaired hearing, insulin-dependent diabetes mellitus and optic atrophy for the diagnosis of Wolfram syndrome. Proper genetic counseling must be given accordingly to patients and their other family members since it is important for their next generation.