Analysis Of Mitochondrial DNA A1555G And C1494T Mutations In 192 Hainan Province Patients With Non-syndromic Hearing Loss

Objective:1.To explore the molecular etiology of 192 cases of non-syndromic hearing impairment patients in Hainan province and to investigate the mutation frequencies of mitochondrial DNA1555A>G and 1494C>T in 192 cases of non-syndromic hearing impairment patients in the region.Screening positive individuals and their maternal members conducted education on the prevention of aminoglycoside antibiotics,aimed at reducing the incidence of drug-induced deafness and be used for genetic counselling and guidance for prepotency.2.To investigate the genetic regularities,clinical auditory features and caries-causing factors in three drug-induced deafness families,and to provide scientific guidance for the development of preventive measures for drug-induced deafness.Methods:1.The mitochondrial DNA A1555 G and C1494 T mutation sites in 192 cases of non-syndromic hearing impairment patients in Hainan Province were detected using Jingxin?Nine Deafness Gene Mutations Detection chips.2.Patients with positive mutations were contacted by telephone to investigate the incidence and medication of their maternal family members,and detailed mapping of genetic lineages.Pure audiometry was used to assess the auditory features of the maternal family members,and then their voluntary blood samples were included in the test.Family members examined mitochondrial DNA A1555 G and C1494 T sites.Results:1.In 192 clinical samples,4 cases of 12 Sr RNA homozygous mutations were detected,and the mutation frequency was 2.08%(4/192).Including 3 cases of 1555A>G homozygous mutation,the mutation frequency was 1.56%(3/192).The 1494C>T homozygous mutation occurred in 1 patient and the mutation frequency was 0.52%(1/192).In the 4 mutation-positive individuals,3 cases were due to exposure to streptomycin and 1 cases had an unknown history of medication.2.Voluntary blood sampling was performed on 14 volunteers from 3 family members,including 11 maternal and 3 spouse controls.Among the 11 maternal members,7 were homozygous A1555 G mutations and 4 were homozygous mutations in C1494 T.The results showed that 7 cases of homozygous A1555 G mutations and 4 cases of C1494 T homozygous mutations were consistent with the detection results of their probands,and their 3 spouses tested normal.The survey results showed that there were 71 cases of maternal familial members in 3 families,and there were 16 cases of deafness patients,all of whom were acquired deafness.Nine cases were impaired by exposure to aminoglycoside antibiotics.Among them,6 were streptomycin,2 were gentamicin-induced,and 1 was caused by kanamycin.The history of drug use in 7 patients with deafness was unknown.Conclusion:1.The homozygous mutation of mitochondrial DNA A1555 G in this study is a common mutation site in the mitochondrial 12 Sr RNA gene in non-syndromic deafness population in Hainan Province.The frequency of mitochondrial DNA A1555 G homozygous mutation in 192 patients with non-syndromic deafness in Hainan Province was 1.56%(3/192),There was no statistically significant difference compared to the average level of domestic reporting(P=0.425).C1494 T The mutation frequency was 0.52%(1/192),which was not statistically different from the detection rate reported in other regions in China(P>0.05).2.In this study,aminoglycoside antibiotics induced deafness gene mutation loci A1555 G and C1494 T all follow the maternal heredity law,has the family aggregation.The deafness was characterized by high frequency descending and sensorineural deafness.Aminoglycoside antibiotics have susceptibility to them.The use of Aminoglycoside Antibiotic is a common cause of deafness in the region.