Detection And Analysis Of Hotspot Mutations In Common Pathogenic Genes Of Hereditary Deafness In Xinjiang

Objective:To investigate and analyze the carrying situation of common deafness genes and hot spot mutations in Han,Uygur,Hui and Kazak populations with hereditary deafness in Xinjiang,and the deafness gene mutations of two Uighur deafness families were detected and analyzed by whole exome sequencing(WES)and Sanger sequencing.Methods: The peripheral venous blood samples of 5860 cases of high risk deafness families and sporadic deaf people in 11 counties and cities in Xinjiang region were collected,and 9 hot-spots of 4common deafness genes were detected by microarray method:GJB2 gene(c.35 del G,c.176＿191del16,c.235 del C,c.299＿300del AT),GJB3 gene(c.538C>T),SLC26A4 gene(c.2168A>G,c.919-2A>G),MT-RNR1(1494C>T,1555A>G);Trace the direct family members of the two screened Uighur families at high risk of deafness,use the whole-exome sequencing technology to identify their pathogenic gene mutations,and perform Sanger sequencing verification on the suspected pathogenic gene mutation sites.Results: A total of1294 people were found to carry deaf-causing gene mutations,with a total mutation rate of22.1%,including GJB2:9.35%,MT-RNR1:7.25%,SLC26A4:4.74%,GJB3:0.29%,and 26cases(0.44%)of double-gene mutations.Mutations in GJB2,MTRNR1 and SLC26A4 genes were detected in high-risk families and sporadic deaf people of four ethnic groups.The highest detection rate of GJB2 gene was 36.02% and 59.81% in Han and Uygur subjects,followed by MT-RNR1 gene and SLC26A4 gene;The detection rate of MT-RNR1 gene mutation was the highest in Hui subjects(43.01%).The homogeneous mutation frequencies of GJB2 gene c.235 del C,SLC26A4 gene c.919-2A>G and MT-RNR1 gene 1555A>G were basically similar in Han subjects;The frequency of homogeneous mutation of GJB2 gene c.235 del C and MT-RNR1 gene 1555A>G occupied the top two in Uighur subjects.The c.35 del G locus was detected only in Uighur and Kazak subjects;The frequency of 1555A>G homogeneous mutation was the highest among Hui subjects.The proband of hereditary deafness family A is a heterozygous mutation at the c169C>A site of GJB2 gene.The Sanger sequencing verification of the three generations of direct deafness family members shows that they are all carriers of heterozygous mutation at this site,and the genotype of normal hearing family members is wild type,which is consistent with family co-segregation.The proband of family B is a homozygous mutation at the c.716T>A mutation site of SLC26A4 gene,and his parents and brother are heterozygous mutations at this site.The c169C>A mutation of GJB2 gene in family A is a new mutation associated with hereditary deafness,and the c716T>A mutation of SLC26A4 gene in family B has been reported in the literature.Conclusion: GJB2 gene and MT-RNR1 gene may be common deafening genes in Han and Uygur populations in Xinjiang;MT-RNR1 may be the most common deafening gene in the Hui population.C.235 del C site and 1555A>G homogeneity may be the hot mutation sites of Han and Uygur populations;C.919-2A>G may be the hot spot mutation site of the Han population;1555A>G homogeneity may be a hot mutation site in Hui population;C.35 del G mutation was only found in Uygur and Kazakh subjects.GJB2 gene mutation may be the pathogenic gene of deafness family A,and SLC26A4 gene mutation may be the pathogenic gene of deafness family B.