FH is caused by mutations in three identified genes that encode key proteins involved in the LDL receptor (LDLr) endocytic and recycling pathways, LDL receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin kexin type 9 (PCSK9), which account for around 90%, 5–10% and 1–5% of FH cases respectively3–5. The gene discussed is APOB; the disease is familial hyperaldosteronism.