APOB and familial hyperaldosteronism: Other forms of monogenic FH are FHCL2 (OMIM#144010), caused by mutation in the apolipoprotein B (APOB) gene and FHCL3 (OMIM#603776) caused by mutation in the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene 5, 6.