FH and atherosclerosis: It has been well established that very high cumulative LDL-C levels significantly accelerate the development of atherosclerosis, and because patients with FH are exposed to markedly increased cholesterol levels for most of their lives, cardiovascular disease (especially myocardial infarction) may manifest at a very early age (in the first decade in untreated homozygotes, after the second decade in severe FH heterozygotes).