RESUMO
OBJECTIVE@#To analyze the prevalence of an A-to-G mutation at nucleotide 1555 of the mitochondrial genome in patients with nonsyndromic hearing impairment (NSHI) of northwest region of China.@*METHOD@#A standardized program of epidemiological design, administrative support, sample collection and mutation screening for mtDNA 12SrRNA A1555G were used performed to study the general condition and the molecular etiology of patients with severe to profound hearing loss from 5 provinces of northwest region of China.@*RESULT@#Five-hundred-seventy-three cases with severe profound hearing loss from 5 provinces were collected and 31 cases were found to carry mtDNA 12SrRNA A1555G mutation.@*CONCLUSION@#Among the patients with severe to profound hearing loss from 5 provinces of northwest region, there was a high proportion of hereditary hearing impairment caused by mtDNA 12SrRNA A1555G mutation. Screening and testing for this mutation are effective methods to prevent ototoxicity in A1555G carriers and their maternal family members.