Spectrum of GJB2 mutations causing deafness in the British Bangladeshi population

Objective: Mutations in Gap Junction Beta 2 (GJB2) (the gene encoding the protein Connexin 26) have been found to be a major cause of non-syndromic sensorineural recessive deafness. The mutations in GJB2 causing hearing impairment vary in different populations. The aim of this study was to determine the prevalence and spectrum of GJB2 mutations in prelingual deafness in a population of Bangladeshi origin in the UK. Design: Cross-sectional survey. Setting: Community based audiology clinic and tertiary level genetics department. Methods: Fifty-three families (67 patients) with sensorineural hearing loss of unknown cause were included in the study. Detailed history and examination excluded syndromic and environmental causes of hearing loss in the subjects as far as possible. Genetic analysis was performed, specifically looking for mutations in the GJB2 gene. Results: Of the 53 families, 14 were confirmed to have biallelic pathogenic mutations in GJB2 (26%). The most common mutations of GJB2 in this population were W24X, IVS1+1, M1V, W77X and Q124X, W24X being the most common mutation seen in 57% of patients. Conclusion: Mutations in GJB2 are responsible for over one quarter of non-syndromic sensorineural deafness in the British Bangladeshi population. It is recommended that all Bangladeshi patients with non-syndromic hearing loss should be first tested for GJB2 mutations before requesting other aetiological investigations.