Objective To study the maternal family history of hearing loss in newborns with mitochondrial 12 S rRNA mutation in Beijing. Methods Family trees were drawn based on genetic counseling. Total maternal family numbers with 12 S rRNA mutation
members with hearing loss and drug using history were analyzed in the maternal family of 140 newborns with 12 S rRNA mutation in Beijing.Results The average maternal family numbers with 12 S rRNA mutation were 13.79
with hearing-impaired family number 1.78. Cases with homoplasmic mutation of m.1555 A>G tended to have hearing-impaired family history(50%) than those with heteroplasmic mutation(11.5%).Conclusion The sensitivity of aminoglycoside antibiotics might be different for homoplasmic or heteroplasmic mutation of m.1555 A>G.