Amongst the 77 individuals fulfilling the clinical criteria for FH, 50 (65%) were found to have a mutation in one of the following genes: LDLR, APOB or PCSK9. None of the subjects had a mutation in LDLRAP1. As expected, xanthomas were more common and pretreatment LDL-C levels were higher in individuals with FH-related mutations compared to those without these mutations. Here, PCSK9 is linked to xanthoma.