Molecular pathogenetic mechanism of maternally inherited deafness.
Mutations in the mitochondrial DNA (mtDNA) have been shown to be one important cause of deafness. In particular, mutations in the mtDNA have been associated with both syndromic and nonsyndromic forms of sensori-neural hearing loss. The deafness-linked mutations often occur in the mitochondrial 12S rRNA gene and in tRNA genes. Mutations in the 12S rRNA gene account for most of the cases of aminoglycoside ototoxicity. The other hot spot for mutations associated with hearing impairment is the tRNA(Ser(UCN)) gene, as five deafness-linked mutations have been identified in this gene. Nonsyndromic deafness-linked mtDNA mutations are often homoplasmic or at high levels of heteroplasmy, indicating a high threshold for pathogenicity. Phenotypic expression of these mtDNA mutations requires the contribution of other factors such as nuclear modifier gene(s), environmental factor(s), or mitochondrial haplotype(s).
Guan
Min-Xin
MX
Cincinnati Children's Hospital Medical Center, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229, USA. min-xin.guan@chmcc.org
D000617:Aminoglycosides / Q000633:toxicity; D000818:Animals; D002460:Cell Line; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D016678:Genome; D034381:Hearing Loss / Q000139:chemically induced / Q000235:genetics* / Q000503:physiopathology*; D006801:Humans; D007231:Infant, Newborn; D009154:Mutation; D009690:Nucleic Acid Conformation; D010641:Phenotype; D012362:RNA, Transfer, Ser / Q000235:genetics
D000617:Aminoglycosides; D004272:DNA, Mitochondrial; D012362:RNA, Transfer, Ser