OBJECTIVETo investigate the prevalence of the mitochondrial DNA (mtDNA) A1555G mutation in nonsyndromic hearing impairment (NSHI) patients from Gansu province.

METHODSSubjects included 802 students selected from five Deaf-Mute Schools in Gansu. DNA was extracted from peripheral blood of all patients. The mitochondrial DNA target fragments were amplified by polymerase chain reaction (PCR). The Mutations were detected by AIw26I digestion and sequence analysis.

RESULTSThe homoplasmic A1555G mutation was found in 67 individuals from 802 patients (8.4%). Fifteen of these 67 patients had family histories.

CONCLUSIONSThe mtDNA A1555G mutation had a higher incidence in Gansu population with nonsyndromic hearing impairment than other studies. The data not only gaven more evidences that the prevalence of mtDNA A1555G mutation in china was higher than that in Europe and America, but also gaven valuable information for gene diagnosis, genetic counseling and would improve the safety of aminoglycoside antibiotic therapy.