Screeing Of The MtDNA 1555 Mutation Gene Associated With Aminoglycoside-Induced Hearing Loss

Background At the beginning of using aminoglycoside antibiotics, the side effect of the severe ototoxicity had been found. The ototoxicity had apparentely individual difference. Study indicated, the sensitivity of aminoglycoside antibiotics induced deafness was associated with mitochondrial inheritance. The mutation of A1555G on the mitochondrial DNA which encoded 12S rRNA gene was one of the most frequently and be reported mutational site which related with aminoglycoside antibiotics induced deafness up-to-now. This mutation had distinct in different races, the Asian has the more. And the sensitivity of aminoglycoside antibiotics induced hearing loss has age associative, the infant who carried the predisposing genes will become deafness more easily when he uses aminoglycoside antibiotics.Objective Through detecting neonate and small infant 12S rRNA gene fragment, to evaluate the frequency of mutation A1555G. And evaluation the significance of screening the mutation of chondriogene associated with aminoglycoside antibiotics induced deafness in our country.Method 300 neonate and small infant hospitalized in newborn nursery were enrolled in this study. Mitochondrial DNA 12S rRNA gene fragment were amplified by polymerase chain reactions (PCR). A1555G mutation was detected by Alw26I restriction endonuclease digestion and by direct sequencing.Results 300 subjects PCR-restriction endonuclease digestion were done. One have no restriction endonuclease digestion site. Mutation A1555G was proved by DNA directed sequencing. Detection rate was 1/300. Another one became two fragments which between 200~300bp after endonuclease digestion. In this subject, the mutation of 16S rRNA A1762G was proved also by DNA directed sequencing.Conclusion In this text, we find a girl has A1555G mutation on the 12S rRNA gene of mitochondrion in 300 subjects who come from Tianjin and its nearby Northern China area.. The exactly frequency of the carrier of mutation 12S rRNA A1555G wants even bigger sample screeing. It is one of the most frequently chondriogene mutation typical associated with aminoglycoside antibiotics induced deafness. The carrier frequency in Asian is higher than it in Caucasian. The aminoglycoside antibiotics sensitivity of mutation carrier has age associativity. The patient who carry A1555G mutayion might be induced hearing loss effected by environmental agent. It is necessary to screen A1555G mutation in neonate and little infant in our country. The A1555G mutation carrier ought to be forbidden using aminoglycoside antibiotics, follow-up visiting their hearing, finding abnormarlity, interfering in time, could reduced hearing loss, hi this study, we find another mutation on mtDNA16S rRNA gene A1762G, its effect is unknow.