Mutations In The GJB2 Gene In Henan Patients With Prelingual Non-syndromic Hearing Impairment

Objective: Through detecting and analysing the mutations of GJB2 gene in Henan province with the unreasonable prelingual non-syndromic hearing impairment people,to explore the relationship between GJB2 gene mutations and the hearing impaiment;reduce the rate of unreasonable prelingual non-syndromic hearing impair-ment;provide evidence and genetic counseling for eary diagnosis,intervention, treat ment.Methods: Extracted genome DNA from the 107 unreasonable prelingual non-syndromic hearing impairment people and 100 normal persons, then detected gene mutation by PCR amplification,purifying PCR product and sequencing,analysed sequencing results and conduct statistical treatment.Results: There are 6 kinds of mutations in GJB2 in the 107 cases hearing loss people,including 3 kinds of deletion and frame shift mutation(235delC 22 cases, 299-300delAT 2cases,176-191del16 lcase),2 kinds of polymorphism(79G > A 30cases,341A>G 37cases),lkind of missense mutation(109G>A 5 cases). There are 3 kinds of mutations in GJB2 in the 100 cases normal people,including 2 kinds of polymorphism(79G > A 29cases,341A > G 38 cases),lkind of missense mutation(109G>A 8cases).The allele frequency of all the mutations in GJB2 is 62.1%(133/214) and 235delC is 15.9%(34/214), so 235delC is the mainly disease-causing mutation in this study.The detection rate between patients group and control group of 109G>A and 79G> A+341A>G is not statistically significant.Conclusion: The GJB2 gene mutation is the key factor causing hearing loss,and 235delC is the main pathogenic mutation site in GJB2 gene. 79G>A and 341 A>G are the main polymorphism, 79G>A homozygosis mutation and 341 A>G homozygosis mutation appearing at the same time are still polymorphism. If we want to distinguish thoroughly that 109G>A is a kind of disease-causing mutation or polymorphism in GJB2,we have to study in some single gene inheritance disease families and screening in a large scale of health people.Sequencing mutations in GJB2 gene is safe,quick and easy,so it could be used in prenatal diagnosis and hearing screening in newborn babies.For an identified deaf person caused by GJB2 gene mutation or a carrier of disease-causing mutation,when their parents wanting to have another child or when themselves get married or having baby,it is advised that they should go to a genetic counseling for professional advice,in order to reduce deaf occurance rate.