Deafness Gene Detection And MYO15A Gene Mutation Analysis In Special Education Schools In Yunnan

Objective:Deafness,as one of the most common disability diseases in the world,seriously affects the language communication and quality of life of patients,and brings severe financial burden to their families.In China,the number of hearing disabled people is about 20 million,which is mainly caused by genetic factors.Part I:Detecting deafness genes in 136 deaf patients from special schools in some regions of Yunnan Province to understand the distribution of deafness genes and their mutation frequencies in deaf patients in Yunnan.Part ?:In the first part of the study,the study found that the mutation site c.4970T>A of MYO15A gene was not reported in the HGMD database.The ESP6500siv2 ALL,1000-person genome(1000g2015aug_ALL),and dbSNP147 databases were not included.The purpose of this study was to analyze the mutation site using biological information software to predict the genetic conservation,pathogenicity,and structural function changes of the mutation siteMothods:Part ?:According to the inclusion and exclusion criteria,136 cases of severe or severe deafness in special schools in some areas of Yunnan Province were selected,the patient information was registered,the history of deafness was asked,and relevant examinations were improved(general physical examination,hearing examination,ENT specialty)an examination).Extract 2-5ml of peripheral venous blood(the patient or patient's guardian has agreed),use a DNA extraction kit to extract genomic DNA,send it to Jincheng Pharmaceutical Company,apply high-throughput sequencing technology for sequencing,and the sequencing depth for nuclear genes is 100×?200 x,using hg19 as the reference sequence of the nuclear gene,to analyze the point mutation and CNV(copy number variation)of the nuclear gene.This test focused on mutations in 518 genes associated with hereditary deafness.Part ?:using T-coffee software,comparing the amino acid sequences of MYO15A protein in different organisms,and analyzing the conservation of human MYO15A protein.Polyphen-2 software was used to predict the pathogenicity of the mutation site.Three-dimensional model of MYO15A protein was constructed by SWISS-MODEL software.Chimera software was used to compare the protein structure before and after the mutation.Results:Part ?:A total of 136 patients with severe-very severe deafness were selected in this study,of which 73 were male and 63 female.The male to female ratio is 1.15:1.There were 28 patients with severe hearing loss(20.5%,28/136)and 108 patients with severe hearing loss(79.5%,108/136).Deafness gene testing was performed on 136 patients,and 89 patients with mutations in deafness were detected,and 47 patients were not detected.The mutation rate was 65.44%(89/136).A total of 65 deafness genes were detected and detected.The four genes with the highest rates were SLC26A4,GJB2,MYO15A,and TMC1.Among them,11 patients had SLC26A4 gene mutation(8.08%11/136),and the hot spot mutation was c.1174A>T(1.47%2/136).GJB2 gene mutation occurred in 7 cases(5.14%7/136),and the hotspot mutation was c.235delC(1.47%2/136).There were 7 cases of MYO15A gene mutation(5.14%7/136),and the hot spot mutation was c.10350+2T>G(1.47%2/136).TMC1 gene mutation occurred in 6 cases(4.41%6/136),and the hotspot mutation was c.1672dupT(1.47%2/136).However,there was only one patient with GJB3 gene mutation,and no patient with mitochondrial 12SrRNA gene mutation was found.Part ?:The research found that using T-coffee software to compare the amino acid sequences of MYO15A proteins in different species,it was found that the 1657th base acid expressed by mutation c.4970T>A was highly conserved in biological evolution.Polyphen software was used to evaluate the pathogenicity of the mutation site,and the result score was 0.098.Based on the model built by SWISS-MODEL software,Chimera software was used to construct the three-dimensional structure of the protein before and after the 1657 amino acid mutation of MYO15A protein.The comparison found that although the surrounding amino acid residues did not change significantly after the mutation,the target amino acid appeared extremely polar.Sexual change.Conclusions:Part ?:The hot deafness genes in Yunnan are SLC26A4,GJB2,MYO15A,and TMC1.Compared with other regions,the mutation frequency of SLC26A4 gene is slightly lower than the national average of 9%,while the mutation frequency of GJB2 gene is lower than the national level,which may be related to Sample size or regional racial diversity.While MYO15A and TMC1 did show a higher ratio,unexpectedly,the GJB3 gene mutation showed a very low mutation rate in this study,only 0.73%(1/136),and no mitochondrial 12S r was found.RNA gene mutations show a large difference between Yunnan and other regions.Yunnan has underdeveloped transportation and is a multi-ethnic region.The deafness genes have also been less studied.This study found the characteristics of deafness genes in Yunnan.It provides a solid theoretical basis for genetic counseling and molecular diagnosis in Yunnan.Part ?:software analysis,in MYO15A protein,the amino acid expressed by c.4970T>A is highly conserved in biological evolution,and the more conservative the gene,the more important the function of the expressed protein is to the organism.Polyphen software was used to evaluate the pathogenicity of c.4970T>A,and the result score was 0.98,indicating that the mutation was highly pathogenic.With Chimera software,the three-dimensional structure of the protein before c.4970T>A mutation and the three-dimensional structure of the protein after mutation were simulated,and it was found that the 1657th is the hydrophobic amino acid isoleucine(Ile)changed to the hydrophilic amino acid aspartic acid(Asn)Later,the polarity of the amino acid changed,and the amino acid expressed in the mutation site c.4970T>A of the MYO15A gene was located in the head(motor domain)of the MYO15A protein.The mutation may cause the function of the MYO15A protein motor domain to be affected.Unfortunately,the parents of the patient with MYO15A gene mutation c.4970T>A(p.Ile1657Asn)are unwilling to draw blood for the deafness gene test.It is not known whether the gene mutation and the deafness phenotype are co-segregated.Further research.