APOB and Hypercholesterolemia: Familial hypercholesterolaemia was initially defined as an autosomal dominant genetic disorder associated with LDLR gene mutations, but presently, heterozygous FH has become more specifically identified as carrying rare genetic variants classified as “pathogenic” or “likely pathogenic” in LDLR, APOB, or PCSK9 genes, or having the p.(Leu167del) variant in APOE according to the American College of Medical Genetics and Genomics (ACMG) guidelines (35).