Clinical Manifestation And Mutation Gene Detection Of Hypertrophic Cardiomyopathy

Objective: To analyze the clinical characteristics of patients with hypertrophic cardiomyopathy and to screen the gene mutation.Methods: The hospital clinical data of 54 patients with hypertrophic cardiomyopathy treated in our hospital(First People’s Hospital of Yunnan Province)from 2015-01 to 2019-03 were collected retrospectively according to the diagnostic criteria of hypertrophic cardiomyopathy.Gene mutation screening was targeted at 25 patients with hypertrophic cardiomyopathy,including 7 patients with familial hypertrophic cardiomyopathy and 18 patients with sporadic hypertrophic cardiomyopathy.The control group was 30 healthy volunteers matched with the patient’s nationality,sex and age.Next-generation sequencing was performed on 30 target genes of hereditary cardiomyopathy.after identifying possible mutation sites,sanger sequencing technology validated this mutation site.Results: There were 54 patients,including 36 males(66.7%)and 18 females(33.3%).The mean age of admission was 50.12±7.08 years(30～68 years),the mean age of onset was 48.56±6.27 years(30 and 67 years),and there was no statistical difference in age at onset between genders(P=0.733).Among the 54 patients,seventeen patients(31.5%)had a history of hypertension,three patients(5.6%)had diabetes,twenty-two patients(40.7%)had atrial fibrillation,and there was no statistical difference in atrial fibrillation between genders(P=0.845).There were 3 probands(5.6%)with a family history of hypertrophic type,and 50(92.6%)and 4(8.4%)patients in Classification of New York Heart Association(NYHA)grades I-II and III-IV,respectively,and there was no statistical difference between genders(P=0.462).Chest tightness and dyspnea(29 patients)and palpitations(18 patients)had the most symptoms.Fourteen patients(25.9%)with apical hypertrophy were diagnosed by echocardiography,and eight(14.8%)had outflow tract obstruction.The maximum thickness of the chamber wall is 1.94 ± 0.29 cm.Mutation sites were detected in MYBPC3,MYH7,TNNI3,TTN,SCN5 A,MYPN genes in 11 of the 25 patients with hypertrophic cardiomyopathy,including 3 FHCM and 4 sporadic hypertrophic cardiomyopathy patients,while the same mutation was not found in 30 normal controls.With the exception of patient 9,patient 55,Family A II:1 and Family A II:2 carrying a single mutation,the other patients carried at least 2 mutation sites.Six mutations,which include 5 missense mutations and a deletion mutation were identified in four patients with sporadic hypertrophic cardiomyopathy.The TNNT2 c.839G>A(R280H)caused 23 mm of Maximum left ventricular wall thickness in patient9.Complex mutation of which comprised MYBPC3 c.2864＿2865del(P955fs)and SCN5 A c.1673A>G(H558R)consists in patient 10.MYH7 c.2155C>T(R719W)and TTN c.10327G>T(E3443X)was identified in patient 11.Patient 55 is a carrier of mutation of SCN5 A c.3416G>A(R1139Q).In Family A,MYPN c.411G>C(R137S)was identified in II:1 and II:2.TTN c.69550T>A(W23184R)just exists in the two patients,but SCN5 A c.3416G>A(R1139Q)was screened in another normal person in Family B.In Family C,more mutations,such as TNNI 3 c.557G>A(R186Q),MYBPC3 c.684T>G(D228E)and SCN5 A c.1673A>G(H558R),were detected,but,SCN5 A c.1673A>G(H558R)was also found in two relatives with normal phenotype except for three HCM patients.Conclusion: In this study,patients with hypertrophic cardiomyopathy were more male than female,the age of onset is similar to the research results at home and abroad,and there was no statistical difference between age and incidence of atrial fibrillation.Symptoms are mainly chest tightness,dyspnea,or palpitations.There are few patients with severe symptoms such as syncope or NYHA III or IV,and about one-third of patients are of apical hypertrophy.MYH7 c.2155C>T(R719W),MYBPC3 c.2864＿2865del(P955fs),TNNI3 c.557G>A(R186Q)are previously known hotspot mutations of HCM.MYH7 R719 W resulted in more severe clinical phenotypes,predisposing to severe heart failure,requiring special attention in clinical work;MYPN c.411G>C(R137S)and TTN c.69550T>A(W23184R)were new mutation sites identified in this screening.