Proteomic profiling of a large cohort of HCM patients: genotype-specific protein changes

Hypertrophic cardiomyopathy (HCM) is characterized by asymmetric left ventricular (LV) hypertrophy and diastolic dysfunction, which leads to LV outflow tract obstruction (LVOTO) in the majority of cases. Mutations in genes encoding sarcomeric proteins cause HCM and are identified in more than half of the patients (sarcomere-mutation positive, SMP). Currently, more than 1500 HCM-causing mutations are known. Approximately 80% of mutations are located in the MYH7 and MYBPC3 genes, encoding for the thick filament proteins β-myosin heavy chain (β-MHC) and cardiac myosin-binding protein C (cMyBP-C), respectively. Less frequent are mutations in the TNNT2 and TNNI3 genes, encoding for the thin filament proteins cardiac troponin T (cTnT) and I (cTnI). Here, we applied an unbiased proteomics approach in a large number of myectomy samples from a clinically well-characterized HCM patient group to define HCM-specific derailments as well as genotype-specific changes at protein level. Our study shows that the downregulation of metabolic pathways and the upregulation of extracellular matrix proteins are the most prominent HCM-specific disease characteristics that are present in all samples independent of their genotype.