PCSK9 and familial hypercholesterolemia: Familial hypercholesterolemia (FH) is a common inherited disorder attributable to mutations in low-density lipoprotein receptor (LDLR), apolipoprotein B (ApoB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and low-density lipoprotein receptor adaptor protein 1 (LDLRAP1), which results in high serum level of low-density lipoprotein cholesterol (LDL-C) [1].