Titin-Truncating Variants Increase the Risk of Cardiovascular Death in Patients With Hypertrophic Cardiomyopathy

Titin-truncating variants (TTNtv) have been detected in a variety of cardiomyopathies and represent the most common cause of dilated cardiomyopathy. However, their significance in hypertrophic cardiomyopathy (HCM) is still unclear.The titin gene (TTN) was sequenced for truncating variants in a cohort of 529 Chinese patients with HCM and 307 healthy controls. Baseline and follow-up clinical data (for 4.7 ± 3.2 years) from these patients were obtained.We identified 13 and 8 TTNtv in patients with HCM (13 of 529 [2.5%]) and controls (8 of 307 [2.6%]), respectively. The prevalence of TTNtv in patients with HCM and in healthy controls was comparable (P = 0.895). There were no significant differences in baseline characteristics between patients with and those without TTNtv. However, during follow-up, patients with TTNtv (3 of 13 [23.1%]) were more likely to experience cardiovascular death compared with those without TTNtv (39 of 516 [7.6%]) [adjusted hazard ratio, 6.88; 95% confidence interval, 2.04-23.20; P = 0.002).Our study suggests that TTNtv might be a genetic modifier of HCM and confer an increased risk for cardiovascular death.