Extreme examples of genetic effects include familial hypercholesterolemias, often caused by defects in the LDLR gene [49], and dyslipidemias arising from mutations in genes encoding APOA4, B, C2, C3, and E [50], PCSK9 [51], and CYP7A1 [52]. This evidence concerns the gene CYP7A1 and familial hypercholesterolemia.