Molecular Finding In Two Chinese Families With Nonsyndromic Hearing Impairment

ObjectiveTo explore the potential role of mitochondrial DNA in the pathogenesis of two Chinese families with non-syndromic and aminoglycoside-induced hearing impairment. MethodsFamily members of two Chinese pedigrees with non-syndromic hearing loss were selected for this study. Detailed history collection and physical examination were conducted. An age appropriate hearing test including pure tone audiometry, acoustic immittance, auditory brainstem response (ABR), and evoked otoacoustic emissions (EOAEs) was performed. Blood samples from 20 family members (13 subjects from pedigree A and 7 from pedigree B) were obtained. Genomic DNA was extracted from the peripheral leukocytes. The subject's DNA fragments spanning the entire mitochondrial DNA 12S rRNA gene, tRNASer(UCN) gene and GJB2 gene were amplified by polymerase chain reaction (PCR). Each fragment was purified and subsequently submitted for direct sequence analysis. ResultsFor pedigree A, family history revealed that 10 of 23 matrilineal relatives...