RESUMO
OBJECTIVE: To identify the possible mutation at possible sites in different mitochondrial genes that leads to hearing loss in a large Chinese pedigree. METHODS: Blood samples from a Hunan pedigree were obtained with informed consent. Genomic DNA was extracted from peripheral blood leukocytes using kit. The target fragments were amplified and detected by polymerase chain reaction (PCR) and directly sequencing respectively. RESULTS: The result of direct sequencing revealed the A1555G mutation in 12S rRNA gene was inherited in this pedigree and no one has A7445G mutation or other mutations in its neighborhood region. CONCLUSION: Sequence analysis confirmed that the pedigree carries the A1555G mutation. With some members ever exposure of aminoglycoside antibiotics, mutation of A1555G may play a pivotal role in the pathogenesis of hearing loss in the large pedigree.
Assuntos
Perda Auditiva/genética , RNA Ribossômico/genética , RNA de Transferência de Serina/genética , Sequência de Bases , China , Análise Mutacional de DNA , DNA Mitocondrial/química , DNA Mitocondrial/genética , Saúde da Família , Feminino , Humanos , Masculino , Casamento , Linhagem , Reação em Cadeia da PolimeraseRESUMO
Deafness is the most prevalent sensory system impairment in human, about 70 % of genetic deafness belongs to nonsyndromic hearing impairment. It was estimated that the total number of genes involved in nonsyndromic hereditary deafness was over 100. So far, approximate 80 loci have been mapped to human chromosome, and 23 genes have been identified. In this paper, a family with nonsyndromic hearing impairment caused by intermarry was reported. There were 13 sufferers in two generations. Deduced from genetic analysis, neither autosomal dominant nor autosomal recessive inheritance was identified in this family, which suggested that hearing impairment in the family was probably caused by mitochondrial mutations.