Targeting the population for gene therapy with MYBPC3

Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited myocardial disease characterized by unexplained left ventricular hypertrophy, diastolic dysfunction and myocardial disarray. Clinical heterogeneity is wide, ranging from asymptomatic individuals to heart failure, arrhythmias and sudden death. HCM is often caused by mutations in genes encoding components of the sarcomere. Among them, MYBPC3, encoding cardiac myosin-myosin binding protein C is the most frequently mutated gene. Three quarter of pathogenic or likely pathogenic mutations in MYBPC3 are truncating and the resulting protein was not detected in HCM myectomy samples. The overall prognosis of the patients is excellent if managed with contemporary therapy, but still remains a significant disease-related health burden, and carriers with double heterozygous, compound heterozygous and homozygous mutations often display a more severe clinical phenotype than single heterozygotes. We propose these individuals as a good target population for MYBPC3 gene therapy.