RESUMO
Objective To explore the relationship between mitochondrial DNA gene,GJB2 gene mutations and the susceptibility to noise-induced hearing loss in the army,and to provide scientific evidence for gene screening of susceptible individuals and relevant molecular epidemiology.Methods 182 blood samples were collected from 349 soldiers,consisting of susceptible and tolerance groups exposed to military noise in Beijing.Genomic DNA was isolated,and the targeted fragments of mitochondrial DNA and coding region of GJB2 gene were amplified by polymerase chain reaction(PCR).The PCR products were analyzed by direct sequencing.Results The results revealed that there were 98 mtDNA variants(41 reside in 12SrRNA) and 12 GJB2 gene variants;among them,mtDNA T1095C and G7642A coexisted in 4 susceptible individuals,but these mutations were not found in the tolerance group.In addition,3 tolerant individuals carried 961delT+insC while no one was found in the susceptible group.Conclusion The 12SrRNA is an area evidenced by high variant and mutation rate.The coexistence of mtDNA T1095C and G7642A in the susceptible group exposed to the similar noise suggests that these mutations are pathogenic mutations associated with NIHL.Three tolerant individuals with the history of long-term noise exposure carry 961delT+insC,suggesting that 961delT+insC might be a conditional pathogenic mutation,but not correlate with NIHL.