Familial Hearing Loss Associated with mtDNA A1555G Mutation in Korea: 1 Pedigree / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Familial aminoglycoside-induced deafness has been described in a number of Chinese and Japanese pedigrees. Recently, the familial aminoglycoside-induced ototoxicity is proved to be associated with a mutation in mitochondrial (mt) 12S ribosomal RNA (rRNA) gene at nucleotide position 1555 in some families. In this study, we analyzed mt 12S rRNA gene to find out this particular mutation in Korean pedigrees who had a family history of hearing loss. MATERIALS AND METHODS: Peripherial blood was obtained from 91 individuals of 30 families, and total genomic DNA (gDNA) was extracted. A fragment of DNA including a part of mt 12S rRNA gene was amplified by polymerase chain reaction (PCR). The PCR products were analyzed by restriction digestion with Bsm A1 and DNA sequencing. RESULTS: We found one family of mtDNA A1555G. Six family members had mutant genotype and three of them showed severe sensorineural hearing loss or deafness. The mutation was homoplasmic in all affected family members, and the genotype revealed maternal transmission. CONCLUSION: We found the first case of familial hearing loss genetically proved to be associated with the mt 12S rRNA gene mutation, in Korea. Because it is possible that an individual with this mutation shows a progressive sensorineural hearing loss, a screening of mtDNA A1555G mutation for the familial members who have a maternal inheritant hearing loss might be necessary.