PCSK9 gene variants are the cause of only 2–4% of ADH; nevertheless, they influence the circulating cholesterol concentration in the general population much more than LDLR or APOB polymorphisms, the other two genes responsible, respectively, of 85–90% and 1–12% of familial hypercholesterolemia [50,51,52]. This evidence concerns the gene PCSK9 and familial hypercholesterolemia.