Introduction
Homozygous familial hypercholesterolemia (HoFH) is a rare inherited hyperlipidemia leading to premature atherosclerotic disease and cardiac events due to extremely high circulating levels of low-density lipoprotein cholesterol (LDL-C) (1). HoFH is caused by bi-allelic pathogenic variants in familial hypercholesterolemia (FH)-causing genes, resulting in dangerously high levels (>400 mg/dL or >10 mmol/L) of LDL-C. The function of these genes is to control how your body regulates cholesterol levels in your blood (2).
Extremely high levels of cholesterol result in plaque deposits in arteries (atherosclerosis) and often leads to serious cardiovascular complications in childhood, like MI and aortic valve disease (3). Buildup of cholesterol can also cause xanthomas around joints and on tendons, corneal arcus in the eyes, and xanthelasmas around the eyelids (4).
