Twenty percent of all childhood deafness is due to mutations in the GJB2 gene (Connexin 26). The aim of our study was to determine the prevalence and spectrum of GJB2 mutations in childhood deafness in Malaysia. We analyzed the GJB2 gene in 51 deaf students from Sekolah Pendidikan Khas Alor Setar, Kedah. Bidirectional sequencing indicates that 25% of our childhood deafness has mutation in their GJB2 gene. Sixty two percent of these children demonstrate V37I missense mutation. Interestingly, V37I mutation in the GJB2 gene have been reported as polymorphism in Western countries, however in our country it behaved as a potentially disease-causing missense mutation, causing childhood deafness as it was not found in the normal control.
One hundred and fifty-five children with childhood deafness were examined over a period of 4 years in order to assess the aetiology of hearing disorder. In 21 (13%) children, deafness was a sequel of meningitis. Perinatal pathology accounted for 34 (22%) cases. The aetiology of deafness was unknown in 44 (28.4%) children. The percentage of unknown causes can be reduced if the deafness is detected early. Hearing loss was diagnosed only in 30 (19%) children by the age of 2 years. The early detection of deafness can be achieved by screening the high risk infants and educating the general practitioners and health assistants.