PCSK9 and Prolonged QT interval: Only two individuals (2/309) had P/LP variants in multiple genes: one harbouring predisposition to familial hypercholesterolemia (FH) and long QT syndromes (PCSK9, KCNH2) and the other with predisposition to cancer and hypertrophic cardiomyopathy (SDHD, MYBPC3).