a1 Department of Otorhinolaryngology and Cervicofacial Surgery, University Medical Centre Ljubljana, Slovenia
a2 Centre for Medical Genetics, University Children's Hospital, University Medical Centre Ljubljana, Slovenia
Objective: Mutations in the gap junction protein beta-2 gene (‘GJB2’) are known to be responsible for mild to profound congenital and late-onset hearing loss. This study aimed to investigate the molecular basis of progressive hearing loss compared with non-progressive hearing loss.
Methods: Following clinical otorhinolaryngological evaluation, a genetic analysis was performed in a cohort of 72 patients with progressive sensorineural hearing loss.
Results: Pathological genotypes were established in 16 patients (22.2 per cent). Six different gap junction protein beta-2 gene mutations were detected in 15 patients, with the c.35delG mutation responsible for 56 per cent of the mutated alleles. A novel gap junction protein beta-6 gene (‘GJB6’) mutation (p.Met203Val) was observed in one patient with mild progressive hearing loss.
Conclusion: Analyses of gap junction protein beta-2 and -6 genes revealed that similar pathological genotypes, occurring with similar frequencies, were responsible for progressive hearing loss, compared with reported genotypes for non-progressive hearing loss patients. Thus, genotype cannot be used to differentiate non-progressive from progressive hearing loss cases; in this study, patients both with and without an established pathological genotype had a similar clinical course.
(Accepted October 21 2011)
(Online publication June 15 2012)
c1 Address for correspondence: Dr Katarina Trebušak Podkrajšek, University Medical Centre Ljubljana, University Children's Hospital, Bohoričeva 20, SI-1252 Ljubljana, Slovenia Fax: +386 1 522 93 57 E-mail: email@example.com
Dr K Trebušak Podkrajšek takes responsibility for the integrity of the content of the paper
Competing interests: None declared