BACKGROUND AND PURPOSE: Mitochondrial DNA (mtDNA) mutation is an important cause of hearing impairment, but its prevalence in Taiwan is not clear. The purpose of this study is to identify mtDNA mutations in subjects with non-syndromic familial hearing impairment in Taiwan. METHODS: During a period of 36 months, 10 families with non-syndromic hearing impairment were enrolled. Screening of mutations in the mtDNA, 12S rRNA, and tRNA(Ser) genes were carried out by polymerase chain reaction, restriction enzyme digestion, and direct sequencing. RESULTS: Among the 10 families examined, four were found to have 1555A-->G mutation in the 12S rRNA gene, one had 7511T-->C mutation in the tRNA(Ser) gene, and one had 7444G-->A mutation of mtDNA. CONCLUSION: Up to 60% of families had mtDNA mutations in this study. Therefore, mtDNA mutation seems to be an important cause of non-syndromic familial hearing impairment in Taiwan.
BACKGROUND AND PURPOSE: Mitochondrial DNA (mtDNA) mutation is an important cause of hearing impairment, but its prevalence in Taiwan is not clear. The purpose of this study is to identify mtDNA mutations in subjects with non-syndromic familial hearing impairment in Taiwan. METHODS: During a period of 36 months, 10 families with non-syndromic hearing impairment were enrolled. Screening of mutations in the mtDNA, 12S rRNA, and tRNA(Ser) genes were carried out by polymerase chain reaction, restriction enzyme digestion, and direct sequencing. RESULTS: Among the 10 families examined, four were found to have 1555A-->G mutation in the 12S rRNA gene, one had 7511T-->C mutation in the tRNA(Ser) gene, and one had 7444G-->A mutation of mtDNA. CONCLUSION: Up to 60% of families had mtDNA mutations in this study. Therefore, mtDNA mutation seems to be an important cause of non-syndromic familial hearing impairment in Taiwan.