PCSK9 gain-of-function (GOF) mutations contribute to familial hypercholesterolemia (FH), an autosomal co-dominant disorder that is most caused by loss-of-function (LOF) mutations in the LDLR gene, or less frequently by ApoB gene mutations that impair lipoprotein binding, leading to ASCVD [27,28]. Here, PCSK9 is linked to atherosclerosis.