Association between Hypertrophic Cardiomyopathy and Variations in Sarcomere Gene and Calcium Channel Gene in Adults

Introduction: Calcium channel gene variations have been reported to be associated with hypertrophic cardiomyopathy (HCM) in family, but the relationship between calcium channel gene variations and HCM remains undefined in the population. Methods: A total of 719 HCM unrelated patients were initially enrolled. Finally, 371 patients were identified based on inclusion and exclusion criteria, including 145 patients with gene negative, 28 patients with a single rare calcium channel gene variation (calcium gene variation), 162 patients with a single pathogenic/likely pathogenic sarcomere gene variation (sarcomere gene variation) and 36 patients with a single pathogenic/likely pathogenic sarcomere gene variation and a single rare calcium channel gene variation (double gene variations). Then the demographic, electrocardiographic, echocardiographic, and follow-up data were collected. Results: Patients with double gene variations were at an earlier age and had more percent of family history of HCM, and had thicker walls, higher left ventricular outflow tract pressure gradient, more pathological Q waves, and more bundle branch blocks as compared with those with single sarcomere gene variation. During the follow-up period, patients with double gene variations had more primary endpoints than the other three groups (p = 0.0013). Multivariate analysis showed that double gene variations were the independent predictor of primary endpoint events in patients (HR: 4.82, 95% CI: 1.77-13.2; p = 0.002). Conclusion: We found that patients with double gene variations had more severe HCM phenotype and prognosis. The pathogenesis effects of sarcomere gene variation and calcium channel gene variation may be cumulative in HCM populations.