Sitosterolemia

**Semantic type:** Disease or Syndrome

**Definition:** An extremely rare autosomal recessive inherited disorder caused by mutations in the ABCG5 or ABCG8 genes. It is characterized by a defective sterolin transporter that impairs the elimination of plant sterols and, to a lesser degree, cholesterol from the body. These fatty substances build up in the tissues including arteries and skin, resulting in atherosclerosis and xanthomas.