Identifying and contacting biological relatives of a person diagnosed with FH (the index case) and then systematically testing these relatives (first-, second-, third-, etc. degree) using a combination of serum LDL cholesterol concentration measurements and a variety of mutation detection or screening assays for mutations in the LDLR, APOB, or PCSK9 genes. The gene discussed is PCSK9; the disease is familial hyperaldosteronism.