| Background:Congenital deafness is one of the most common human diseases, more than 50% are caused by genetic factors, non-syndromic deafness is the most common hereditary, has found more than ten loci associated. Which, GJB2 gene because of its high rate of genetic mutation rather small and abroad in recent years become a hot research. In addition,drug-induced deafness associated with mitochondrial gene mutation accounts for hereditary deafness 1%-2%. hotspot mutations in mt DNA point mutations is a high incidence of deafness gene mutations and proved to aminoglycoside-induced and non-syndromic deafness.Objective:Mutations of 1011 non-syndromic deafness of special education and language training school in Shanxi were screened in GJB2 gene and mt DNA 12 S r RNA gene 1555,to explore the incidence of GJB2 gene and mt DNA 1555 sites and hotspot mutations in the region, provide the basis for future gene therapy and prevention of deafness. 20 cases were selected to detect by gene chip, hot spot mutation in Shanxi area were screened by chip technology deafness gene.Methods:1. To collect and collate all the clinical symptoms of deafness in the region, the patients with non-syndromic deafness specimens were labeled and extracted the corresponding genomic DNA.2. The GJB2 gene and mt DNA 12 S r RNA gene 1555 were designed specific primers and amplified and sequenced simultaneously in vitro, and then with the corresponding gene sequences were compared to normal, acquire the mutations information of deafness patients in the area.3. 20 cases were randomly selected in 1011 specimens of deafness, gene diagnosis were conducted by gene chip technology from Affynetrix Cyto Scan 750 K.Results:1. 232 individual in GJB2 gene mutations occurred in 1011 patients, the rate was22.95%. A total of 35 mutations were detected: c.IVS1-35, c.21G-T, c.30-35 del C,c.35 del G, c.54C-A, c.79G-A, c.88A-G, c.109G-A, c.127G-C, c.139G-T, c.167 del T,c.176-191del16, c.186C-T, c.187C-T, c.199C-T, c.223C-T, c.226C-A, c.235 del C,c.253T-C, c.270A-C, c.271G-C, c.277A-G, c.283G-A, c.299-300 del AT, c.319A-G,c.328 del G, c.336G-T, c.341A-G, c.368C-A, c.457G-A, c.512-513 ins AACG, c.553C-T,c.558G-A, c.608T-C, c.765T-C. In which, c.79 G-A, c.341 A-G, c.457G-A, c.608T-C,c.765T-C belongs to the polymorphic loci, respectively, the mutation rate was 32.15%,28.39%, 0.10%, 2.67%, 6.82%; new mutations was found in 11 cases of c.IVS1-35,c.127G-C, c.558G-A, c.512-513 ins AACG, c.512-513 ins AACG, c.88A-G, c.186C-T,c.187C-T, c.199C-T, c.277A-G, c.319A-G. In all mutations, the rate of c.235 del C is highest, at 13.06%; followed by c.299-300 del AT(3.17%), c.109G-A(2.47%), c.368C-A(1.38%), c.176-191del16(1.19%).2. 15 patients were detected mt DNA 1555A-G in 1011 patients, the mutation rate was 1.5%(15/1011).3. 18 cases in 20 patients were detected by Cyto Scan 750 K chip from Affynetrix company, there are no association of variation between the tested samples and the database of known deafness gene, but No.7, 9 and 11 were found have similar duplication,No.4 was detected have larger deletions, and major duplicatiothe on Y chromosome, other samples also shows some duplication or deletion.Conclusion:1. Deafness The mutations in GJB2 gene mutation rate was the highest in shanxi area,in the deaf nationwide epidemiological findings are consistent with the Daipu;2. In the region to complete deafness gene mutation screening and statistics,providing a theoretical basis for the early diagnosis and treatment of deafness region, to provide a reliable theoretical basis for future clinical work carried out in the area of deafness mutations create the database Shanxi database for mutations in other regions deafness has laid a solid foundation for the establishment, but also enrich the database of deafness.3. Related gene mutation detection was performed in 18 patients with deafness Usingthe gene chip, the rate is low, and probably due to the high cost of gene chip, the detection of less samples. These need to expand the sample to investigate further. |
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