Homozygous sitosterolemia is an autosomally inherited recessive disorder of sterol metabolism. Patients with homozygous sitosterolemia can present with accelerated atherosclerosis with initial CHD events occurring in childhood. In addition, these patients can have tendon xanthomas, hemolytic episodes, as well as arthritis and arthralgias. Plasma levels of sitosterol and other dietary sterols are markedly elevated in homozygous sitosterolemic patients, and are diagnostic of this disorder. A low sterol diet provides only limited reduction in sitosterol levels and currently available medical treatments, such as bile salt binding resins, are usually insufficiently effective or poorly tolerated.