Outcome Study Of Cochlear Implantation Based On Genotype-phenotype Analysis Of Hearing Impairment And Study Of ATP6V1B2 Defective IPSC Establishment And Gene Correction

More than 60%of congenital hearing loss（HL）is caused by genetic factors.Cochlear implant（CI）is the only effective method to solve severe to profound HL.Deafness genetic testing is helpful to accurately diagnose deafness and predict the postoperative effect of CI.Patients with multiple deafness gene variants achieved satisfactory auditory performance after CI,suggesting that identifying genetic background is helpful to predict the performance after CI.However,the postoperative effect of CI in some patients is not satisfactory.The progress in the field of induced stem cells（iPSC）brings opportunities for the development of biological therapy based on human auditory sensory cells and provides opportunities to understand the pathogenesis of HL and determine new treatment strategies.Part Ⅰ.Genotype-phenotype analysis on hearing loss and rehabilitation effect after CIObjective:Based on the genomic information of patients with hereditary HL,make accurate classification and diagnosis of deafness,design individualized prevention and treatment plan for patients with hereditary HL,and realize precise medical treatment of hereditary deafness.Methods:There were 251 probands tested by whole exome sequencing（WES）.The correlation between genotype and phenotype was analyzed,and the postoperative effects of CI in patients with different deafuess genes were compared.Aiming at the third common deafness gene MYO15A in the study,the genotype-phenotype correlations of 81 MYO15A-related HL patients from 2263 were analyzed retrospectively by WES and deafness gene targeted sequencing.Results:According to the analysis of WES results,GJB2 and SLC26A4 were the most common pathogenic genes of HL and had the better effect after CI.Patients with syndromic HL have poor postoperative effect due to complex causes of HL.There was significant difference in the postoperative effect of CI in patients with unknown pathogenic gene.The frequency of MYO15A gene was 3.58%（81/2263）,and c.10245₁0247delCTC is the most common recurrent variant.The phenotypes associated with MYO15A were diverse.Conclusion:Different deafness pathogenic genes are related to the postoperative effect of CI.The results of gene diagnosis can be used as one of the effective factors to predict the performance after CI.And gene diagnosis can promote the decision of early intervention.MYO15A is a common deafness gene in China.Screening for MYO15A variants in deaf patients is very necessary for effective gene diagnosis,patient consultation and clinical intervention.Part Ⅱ.Establishment and gene correction of iPSC line from a patient with ATP6V1B2 gene deficiency Objective:Dominant deafness nail dystrophy syndrome（DDOD）is a rare autosomal dominant disease.ATP6V1B2 c.1516 C>T（p.Arg506*）is the cause of DDOD syndrome.The iPSC line carrying the mutation was established for in vitro modeling to better understand the pathogenesis of DDOD and explore potential therapeutic targets.The mutation of the cell line was corrected by CRISPR/Cas9 to further explore the effect of gene therapy on DDOD syndrome.Methods:The iPSC line was established by episomal vector using peripheral blood mononuclear cells of DDOD patient with ATP6V1B2 c.1516 C>T heterozygous mutation.And it was corrected by CRISPR/Cas9 mediated homologous recombination technology.The established and corrected iPSC line were both identified.Results:Both the established and the gene corrected iPSC line had normal karyotype and were tested by immunofluorescence staining to detect the major pluripotent protein markers and differentiated into all three germ layers.Conclusion:The iPSC line with similar characteristics to ESC were successfully established by episomal vector,and the gene corrected iPSC was successfully screened by CRISPR/Cas9.Both have the potency of differentiation in vitro and can be used as a useful model to study the pathogenesis and treatment of DDOD syndrome.