Association Analysis And Transcriptomics Study Of Genotype-phenotype-pathological Changes Of Hypertrophic Obstructive Cardiomyopathy

Background:Hypertrophic cardiomyopathy(HCM)is one of the most common hereditary cardiomyopathy and one of the most common causes of sudden death in young people and athletes.HCM is highly heterogeneous with a diverse anatomy,pathophysiology,and clinical course.The main causative genes are eight key genes encoding sarcomeric proteins,and 80%of the detected HCM mutations located in MYBPC3 or MYH7,which encode constituents of the thick flament proteins(cardiac myosin-binding protein C and ?-myosin heavychain).Previous studies have shown that genotypes are associated with specific phenotypes in HCM patients,but it is still uncertain whether there is a correlation between histopathological changes and genotypes;and the regulatory network of HCM pathogenesis is largely unknown.The main purpose of this paper is to comprehensively study the effects of genotypes on clinical phenotypes,pathological changes,and disease transcriptomics.Methods:A 93-cardiomyopathy-related-gene panel was used to screen 193 Chinese patients with hypertrophic obstructive cardiomyopathy(HOCM),and whole exome sequencing was used to screen 173 Chinese patients with HOCM.The pathogenicity of all variants was classified into 6 categories according to American College of Medical Genetics and Genomics(ACMG),pathogenic(P),possible pathogenic(LP),and uncertain significance(VUS),likely benign,and benign,and VUS-LP(indicating that only one lack of supporting evidence can be upgraded to a possible pathogenic mutation site).The correlation between genotype and clinical phenotype of HOCM was analyzed.At the same time,the effect of genotype,clinical phenotype and pathological changes in HOCM patients was studied.Thirty patients with HOCM were selected from the samples that had been genetically tested.These patients were divided into three groups according to the different gene mutation sites:MYBPC3 group,MYH7 group and non-variant group.Nine healthy donors were selected to extract RNA from left ventricular tissue for RNAseq.The differentially expressed genes and IncRNA and the co-expressed genes in each group were analyzed by various bioinformatics methods,and then clustered according to signal pathway and molecular function.The abnormal splicing events are predicted and verified.Finally,the special cases were analyzed and summarized.Results:365 rare mutations were detected in 11 genes,of which likely pathogenic/pathogenic accounted for 50.5%.The pathogenicity of variants in HOCM patients may be more important than the number of sites.The presence of variant,regardless of the number,is associated with early diagnosis and LV dysfunction.In addition,the proportion of children with VUS-LP or LP/P is as high as 76.5%,and only 12.8%of patients do not carry any suspicious variants.Patients with variant sites,whether VUS or LP/P,had a lower age of diagnosis than patients who did not carry any variant sites(P<0.0001);the posterior wall of the left ventricle in the LP/P group was thinner(P=0.0009),and the final appearance of the interventricular septum was significantly thicker than the non-variant group(P=0.0025),but there was no statistical difference between the VUS group and the non-variant group;the LP/P group was more likely to have a family history(P=0.0008).Patients with LP/P variants had significantly increased cell hypertrophy(P=0.026),cardiomyocyte disorder(P=0.006),and interstitial fibrosis(P=0.036)compared with patients without any mutation,while carrying VUS There were no significant differences in the patients.A total of 21612 coding and 7008 lncRNA genes were evaluated for differential expression.In addition,373 differentially expressed genes(DECG)and 150 differentially expressed lncRNA genes(DELG)were identified in the myocardium of HOCM patients compared to the control group.The variability in the expression levels of these DEGs can be observed in HOCM patients with different mutation sites(MYBPC3,MYH7 or no variation),and there is no difference between the groups,but can be clearly divided into two parts with the control group.The seven splice variants predicted by computer tools in the DNA sequencing data were verified at the RNA level of cardiac tissue,and six were confirmed to cause abnormal splicing.In addition,splicing events in three cardiomyopathy-related genes were also found by RNAseq data analysis.Finally,we detailed analysis of 3 family lineage of WES identified with pathogenic variation.Conclusion:This article,for the first time,reveals the impact of genotypes on patient clinical characteristics,including the number and pathogenicity of variant sites,as well as histopathology and certain tables,through large-scale tissue biopsy and Panel genetic screening.The impact of type changes.This approach not only fills the gaps between genotype and histopathological changes in HCM patients,but also helps predict clinical outcomes.The RNAseq of myocardial tissue revealed significant differences in transcription levels in the myocardium of HOCM patients compared to normal myocardial tissue.This paper shows that gene sequencing is of profound significance in the clinical management of HOCM patients,and the combination of RNAseq data will have better clinical application prospects.