Sitosterolemia.
Sitosterolemia was first described 28 years ago in two sisters. They had tendonxanthomas, normal plasma cholesterol levels, and elevated plant sterol levels. The high plant sterol levels were shown to be due to the increased absorption and delayed removal of plant sterols from the body. The increased absorption of plant sterols does not affect cholesterol absorption in these patients. However, cholesterol biosynthesis pathway is downregulated and turnover rates are reduced. Bile acid binding resins and ileal bypass surgery are effective treatments for sitosterolemic patients, whereas statins are ineffective. Sitosterolemia is inherited as a recessive trait. Recent studies have shown that mutations in ABCG5 and ABCG8 genes contribute to sitosterolemia. Most likely, ABCG5 and ABCG8 proteins function as obligate heterodimers and play a role in the absorption of plant sterol or control their rate of absorption.
Salen
Gerald
G
VA Medical Center, 385 Tremont Avenue, East Orange, NJ 07081, USA. salenge@umdnj.edu.
Patel
Shailesh
S
Batta
A K
AK
D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D000071019:ATP Binding Cassette Transporter, Subfamily G, Member 8; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000042:Absorption; D002784:Cholesterol / Q000096:biosynthesis / Q000378:metabolism; D015536:Down-Regulation; D006579:Heterozygote; D006801:Humans; D000960:Hypolipidemic Agents / Q000627:therapeutic use; D008052:Lipid Metabolism, Inborn Errors / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D008074:Lipoproteins / Q000235:genetics; D012855:Sitosterols / Q000097:blood* / Q000737:chemistry; D013997:Time Factors
C416945:ABCG5 protein, human; C416946:ABCG8 protein, human; D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D000071019:ATP Binding Cassette Transporter, Subfamily G, Member 8; D018528:ATP-Binding Cassette Transporters; D000960:Hypolipidemic Agents; D008074:Lipoproteins; D012855:Sitosterols; D002784:Cholesterol