Prevalência e fenótipo clínico de pacientes com Cardimiopatia Hipertrófica associada aos genes Myh7 e Mybpc3 em um ambulatório de Cardiogenética

Abstract

Hypertrophic cardiomyopathy (HCM) is the most common genetically inherited heart disease and is frequently associated with mutations in the MYH7 and MYBPC3 genes. However, the literature lacks studies on the prevalence of these mutations and the health profile of affected individuals. Therefore, this study aimed to clinically, epidemiologically, and genetically characterize individuals with HCM due to mutations in MYH7 and MYBPC3. This is a cross sectional, observational, and quantitative study conducted in a Cardio-Genetics outpatient clinic in Sergipe, Brazil. A convenience (non-probabilistic) sample was obtained, including individuals with a confirmed diagnosis of HCM through echocardiography or cardiac magnetic resonance imaging. Clinical and epidemiological data were collected through medical record reviews and structured interviews, including information on age, sex, family history, lifestyle habits, comorbidities, and medication use. Genetic analysis was performed using buccal swab samples sent to a reference laboratory for sequencing of 19 genes associated with HCM and phenocopies. Data were analyzed descriptively and inferentially with a significance level of 5% (α = 0.05). A total of 130 individuals (N = 130) were included in the study, of whom 96 (73.8%) had a positive genetic test, with 56 (43.1%) carrying clinically significant variants. The prevalence of MYH7 mutations was 41.1%, while MYBPC3 mutations were present in 12.5%. Left ventricular hypertrophy was the most common comorbidity (91.1%), and the most frequent symptoms were palpitations (71.4%) and dyspnea (51.8%). Female predominance was observed among individuals with MYH7 (65.2%) and MYBPC3 (71.4%) mutations, while other mutations were more prevalent in males (57.7%). A family history of sudden cardiac death was present in 66.1% of cases, significantly lower among MYBPC3 carriers (p-value = 0.023). Regarding treatment, beta-blockers were the most frequently used drugs (69.6%). In conclusion, mutations in the MYH7 and MYBPC3 genes play a central role in HCM, being associated with a heterogeneous clinical spectrum. This study reinforces the importance of genetic evaluation for a more individualized clinical management of affected individuals.