Less commonly, the FH phenotype may be caused by mutations in other genes, specifically apolipoprotein B (APOB), which encodes the ligand of the LDL receptor, and PCSK9, which encodes the enzyme proprotein convertase subtilisin/kexin type 9, which is involved in regulating the degradation of the LDL receptor; very rarely, mutations also occur in other genes, e.g., APOE [1]. The gene discussed is PCSK9; the disease is familial hyperaldosteronism.