Mutation Site Screening In Hypertrophic Cardiomyopathy And Genotype-phenotype Correlation Analysis

Objective: Sudden cardiac death(SCD)is the most serious complication of Hypertrophic cardiomyopathy(HCM),especially in young adults and athletes.At present,due to the lack of a specific explanation for mutations and the lack of the extensive application of forensic molecular anatomy techniques,accurate identification of HCM patients has always been a difficult problem.The purpose of this study was to study the gene mutation of HCM group,in order to find new pathogenic mutations,analysis of HCM patients between genotype and phenotype correlation,achieve the goal of early diagnosis and early intervention.To improve the accuracy of identification of cause of death in sudden death cases,promote the investigation of cases,and provide objective scientific evidence for clinical medicine and forensic pathology.Methods: In this study,14 unrelated HCM probands received treatment in the Affiliated Hospital of Qingdao University from 2018 to 2019 were collected as the experimental group.The control group of 307 healthy volunteers who showed no abnormalities on electrocardiogram and echocardiogram and no other disease that increased cardiac stress.The diagnosis of HCM conformed to the 2014 European Society of Cardiology criteria.All probands were genotyped by whole exome or panel sequencing.Family members and healthy control group were validated by Sanger sequencing.We collected the Clinical data of subjects,including medical history and imaging examination,and analyzed the associations between the genotypes and phenotypes of the mutant carriers.The classifications of variation were referenced to CLINVAR database and ACMG Standards and Guidelines for Classification of Genetic Variations.The occurrence of mutations in the population was determined by searching db SNP and 1000 Genomes database.A variety of bioinformatics software such as Polyphen-2,Mutation Taster,GERP++and SIFT were used to predict the pathogenicity of mutant proteins and Clustal X software was used to analyze the conservatism among species.Results:1.Eleven of the 14 probands carried the genetic mutation.A total of 17 mutation sites were detected,including 8 MYH7 genes(47%),4 MYBPC3 genes(23.5%),3 TNNT2 genes(17.6%),1 MYL3 gene(5.9%),and 1 TPM1 gene(5.9%),all of which were missense mutations.Four people(28.6%)were multiple gene mutant carriers and seven(50%)were single gene mutant carriers.Among them,TPM1-Ile154 Val and MYBPC3-Tyr1251 Ser are new mutations,which have not been reported at home and abroad.The healthy controls of 307 people did not carry the mutation;2.There were 8 probands who had experienced syncope,and the severity of the clinical symptoms varied,mainly manifested as palpitation,chest pain,dyspnea,etc.3.According to the comprehensive analysis of database,Clustal X and bioinformatics software showed that mutations of MYH7-Arg249 Gln,MYH7-Arg143 Gln and TPM1-Ile154 Val can cause HCM.Conclusions: TPM1-Ile154 Val and MYBPC3-Tyr1251 Ser missense mutations are new mutations,which do not exist in normal population and have not been reported at home and abroad.It was verified that mutations of MYH7-Arg249 Gln and MYH7-Arg143 Gln could cause HCM,and the phenotypes of carriers were consistent with the reports.The results of genetic screening of patients is helpful to expand the mutation spectrum of HCM,which is conducive to understand the relationship between genotype and phenotype,and is also helpful to forensic to provide objective and fair evidence in the cases of sudden death,and has certain value in identifying the cause of death.It is of great significance to the practice of forensic pathology.