Although all subjects fulfilled the clinical diagnosis of FH, it is possible that a small proportion of those designated as “polygenic” may carry an FH-causing mutation in the LDLR/APOB/PCSK9 genes that has been missed because of technical reasons in the methods used for mutation detection, although this is unlikely to be more than 1–2 for each of the study groups. Here, PCSK9 is linked to familial hyperaldosteronism.