Accumulation of dietary cholesterol in sitosterolemia caused by mutations in adjacent ABC transporters.
In healthy individuals, acute changes in cholesterol intake produce modest changes in plasma cholesterol levels. A striking exception occurs in sitosterolemia, an autosomal recessive disorder characterized by increased intestinal absorption and decreased biliary excretion of dietary sterols, hypercholesterolemia, and premature coronary atherosclerosis. We identified seven different mutations in two adjacent, oppositely oriented genes that encode new members of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family (six mutations in ABCG8 and one in ABCG5) in nine patients with sitosterolemia. The two genes are expressed at highest levels in liver and intestine and, in mice, cholesterol feeding up-regulates expressions of both genes. These data suggest that ABCG5 and ABCG8 normally cooperate to limit intestinal absorption and to promote biliary excretion of sterols, and that mutated forms of these transporters predispose to sterol accumulation and atherosclerosis.
Berge
K E
KE
Department of Molecular Genetics and McDermott Center for Human Growth and Development and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9046, USA.
Tian
H
H
Graf
G A
GA
Yu
L
L
Grishin
N V
NV
Schultz
J
J
Kwiterovich
P
P
Shan
B
B
Barnes
R
R
Hobbs
H H
HH
D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001646:Bile / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D002791:Cholesterol, Dietary / Q000008:administration & dosage / Q000378:metabolism*; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2; D003062:Codon; D004268:DNA-Binding Proteins; D020224:Expressed Sequence Tags; D005786:Gene Expression Regulation; D006801:Humans; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D008052:Lipid Metabolism, Inborn Errors / Q000235:genetics* / Q000378:metabolism; D008074:Lipoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D000071518:Liver X Receptors; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009154:Mutation; D057093:Orphan Nuclear Receptors; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D012855:Sitosterols / Q000097:blood* / Q000378:metabolism
C416945:ABCG5 protein, human; C462600:ABCG5 protein, mouse; D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D018528:ATP-Binding Cassette Transporters; D002791:Cholesterol, Dietary; D003062:Codon; D004268:DNA-Binding Proteins; D008074:Lipoproteins; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D012855:Sitosterols; D002784:Cholesterol