背景
The protein encoded by this gene is a member of the superfamily of ATP-binding cassette
(ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular
membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP,
ALD, OABP, GCN20, White). This protein is a member of the White subfamily. The protein
encoded by this gene functions to exclude non-cholesterol sterol entry at the intestinal level,
promote excretion of cholesterol and sterols into bile, and to facilitate transport of sterols
back into the intestinal lumen. It is expressed in a tissue-specific manner in the liver,
intestine, and gallbladder. This gene is tandemly arrayed on chromosome 2, in a head-tohead orientation with family member ABCG5. Mutations in this gene may contribute to sterol
accumulation and atherosclerosis, and have been observed in patients with sitosterolemia
