The development of powerful hypolipidemic drugs, such as proprotein convertase subtilisin/kexin type 9 (PCSK9), which may be optimally combined with L-thyroxine (L-T4) to treat severe forms of familial hypercholesterolemia and hypothyroidism has opened up a new field of research investigating the underlying mechanisms connecting thyroid function to lipids (13). This evidence concerns the gene PCSK9 and familial hypercholesterolemia.