ABSTRACT
It is well known that sensorineural heating loss(SNHL) may be frequently associated with mitochondrial DNA(mtDNA) mutations. Mitochondrial DNA mutations associated SNHL have previously described in aminoglycoside-induced hearing loss(A1553G in the mitochondrial 12S ribosomal RNA gene) and diabetes with hearing loss(A3243G in the mitochondrial transfer RNA(Leu(UUR)) gene. The authors report a case of SNHL and diabetes mellitus associated with mtDNA mutation(A3243G). Patient had adult-onset maternally inherited diabetes mellitus. The SNHL appeared to be in progess since adolescence and was bilateral and symmetric. Bilateral hearing was impaired in all frequencies and was deteriorated more severely at high frequencies. Audiometric test results suggested that hearing loss involved in the cochlear rather than the retrocochlear. The point mutation of mtDNA should be suspected in patients with progressive cochlear hearing loss when they also have a family history of diabetes and/or hearing impairment.