Epidemiology Investigation Of Syndrome Type Deafness Mutation Gene From Hebei Xingtai Area

Objective: China increase about 900000 birth defects in newborns each year. Deafness is one of the most common genetic disorder. Previous studies show that there are many reasons for causing deafness, among which are genetic factors, about half of deafness is caused by the genetic defect. Which bring heavy burden to family and society of its high incidence and low cure rate. With the discovery of hereditary deafness related genes and in-depth study of mechanism of deafness, make deaf molecular diagnosis, prevention and treatment of tertiary system are rich. This study focused on analyzing mutations of coding sequence of common deafness syndrome deaf, the rapid genetic diagnosis lay the foundation for deaf.Methods:1 The object of study and information acquisition: 110 non-syndromic hearing loss(NSHL) patients from xingtai special-education schools.Which all entrants to the whole body physique, pure tone audiometry and sound immittance test. 110 non-syndromic hearing loss(NSHL) patients were interviewed for medical histories of hearing loss, use of aminoglycosides, and other clinical abnormalities using questionnaires.2 Samples: Collect 110 cases non- syndromic hearing loss(NSHL) patients the syndrome in patients with type deafness blood specimens, store in-80 refrigerator, establish blood specimens library.℃3 The expression of mitochondrial DNA 12 S r RNA, GJB2, GJB3 and SLC26A4 gene expression were detected by using polymerase chain reaction(PCR) methods.4 Application directly sequenced to detect the mutations of GJB2 gene sequencing method, mitochondrial DNA 12 S r RNA gene, GJB3, and SLC26A4 gene. Using Gene Tool Lite 1.0 software will get the sequence of DNA sequencing results and the NCBI site search to the standard of GJB2 sequence(NC-000013.9) and GJB3 standard(NT-004511), standard of SLC26A4 sequences(NC-000007-13) and the standard of mt DNA sequences(NC-001807) compare analysis, in order to screening the presence of mutations.Results: The hearing loss in the classification standard assess 110 cases of Xingtai city in hebei province deaf students school, 110 cases were diagnosed as bilateral deafness and are based on syndrome type deafness. In 110 an example research object, 8 of the inner ear SLC26A4 mutations in the most common deformity vestibular conduit expand(enlarged vestibular agueduet, EVA). 110 cases of research object, the respondents before or the deaf pregnancy used clear aminoglucoside the class antibiotic 20 cases, of which the most used alone gentamycin with 12 cases, used amikacin with 2 cases, small’s amikacin with 3 cases, combination in patients with streptomycin gentamycin in 3 cases. The use of drug time mainly focus on the research object infants or its mother during pregnancy, used more for a cold, fever and diarrhea, concrete the dosage is unknown. 110 patients were diagnosed with non-syndromic hearing loss(NSHL), 2 causes(1.8%) carried mitochondrial A1555 G mutation, and 2 causes(1.8%) carried mitochondrial C1494 T mutation; 11 causes(10%) showed homozygous GJB2 235 del C mutation, and 11 causes(10%) showed compound heterozygous GJB2 mutation; 5(4.5%) carried homozygous SLC26A4 IVS7-2A>G mutation, and 7(6.4%) had heterozygous SLC26A4 IVS7-2A>G mutation. Three patients carried two unclassified mutations in GJB3 genes. Overall 38 mutant variants were detected in this cohort of patients, including in dittion also found 5 novel mutations in SLC26A4. The 5 novel variants were 4 missense substitutions(p.G222 S, p.A456 D, p.N457 I, p.F667L) and one nonsense mutation(p.W472X).Conclusions: The most common deafness gene of GJB2 gene mutations, followed by SLC26A4 gene mutations for the high incidence of hereditary NSHL deafness in Xingtai area. Although mt DNA 12 S r RNA gene mutation is not deafness main reason in the region, but its mutation screening can predict individual genetic susceptibility to Am An, provide guidance for clinical rational drug use, effectively reduce the incidence of drug-induced deafness. As a result, the GJB2, GJB3, SLC26A4 and mt DNA 12 S r RNA gene as xingtai area clinical routine screening project, at the same time in order to further carry out genetic counseling and prenatal diagnosis and genetic diagnosis provides an important theoretical basis.