FH is an autosomal dominantly inherited disorder of lipid metabolism. Heterozygosity has an estimated prevalence of 1:500. It is caused by mutations in the LDL receptor gene. Total and LDL cholesterol are severely increased. Generally the triglyceride levels are normal. Tendon xanthomas (in particular Achilles' tendons) are pathognomic, but atheromas are the most important consequence of the disorder.