An analysis of the mutation in GJB2，GJB3，SLC26A4 and mtDNA12SrRNA in new born

Abstract

Objective:To analyze deafness gene mutation in GJB2，GJB3，SLC26A4 and mtDNA12SrRNA in newborn and to explore the significance of genetic test and potential correlations between the genotype and clinical phenotype.Method:Blood samples were collected with a standard protocol and DNA templates are extracted from 501 newborn in Longgang of Shenzhen.MALDI-TOF-MS Technology was used to detect the coding region twenty mutations sites of GJB2，GJB3，SLC26A4 AND mtDNA12SrRNA，includingSLC26A4(1226G>A,1229C>T,281C>T,589G>A,IVS7-2A>T,1174A>T,IVS15+5G>A,1975G>C,2027T>A,2162C>T,2168A>G),GJB2(176-191del16,35delG,167delT,235 delC,299-300 delAT),GJB3(547G>A,538C>T),mtDNA12SrRNA(1555A>G,1494C>T).While two-step hearing screening was carried by using AABR（automatedauditory brainstem response）and DPOAE. Result:In the 501 newborns,26 cases were found have one or two allele mutations of deafness-susceptibility genes.GJB2 gene mutation(n=9,1.796%) all were 235 delC single heterozygosity mutation.GJB3 gene mutation(n=3,0.599%). SLC26A4 gene mutation(n=12,2.395%) included IVS7-2A>G heterozygosity mutation(n=5). MtDNA 12Rrna gene mutation was found in 3 child(n=3,0.599%). Finally one of 26 infants was diagnosed enlarged vestibular aqueduct syndrome. The infant was detected 2168A>G heterozygosity mutation. Conclusion:235delC is the main mutation form of GJB2 gene,while it is the hottest mutation in People. But SLC26A4 gene mutations are the main type in newborn. MtDNA 12Rrna gene mutation was found in 3 child.This genetic epidemiological study demonstrated that genetic screening is helpful for determining high risk individuals and early discovering possible late-onset hearing loss. Moreover pationts and family member can acquire more effective genetic counseling.