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.
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.
Recently, we reported that a novel member of the ABC-transporter family, named "sterolin-1" and encoded by ABCG5, is mutated in 9 unrelated families with sitosterolemia; in the remaining 25 families, no mutations in sterolin-1 could be identified.
Interestingly, mutation of ABCG5 and or ABCG8 genes in man causes sitosterolemia, a rare genetic disease characterized by massive absorption of plant sterols and premature arteriosclerosis.
A female subject with each mutation was symptomatic with coronary atherosclerosis: a 5-year-old ABCG8 S107X homozygote and a 75-year-old ABCG5 exon 3 I/D homozygote; these represent the extreme ends of the spectrum of vascular involvement in sitosterolemia.
We conclude that the majority of the molecular defects in G5 and G8 that cause sitosterolemia impair transport of the sterol transporter to the cell surface.
Similar serum plant sterol responses of human subjects heterozygous for a mutation causing sitosterolemia and controls to diets enriched in plant sterols or stanols.
The gene(s) causing sitosterolaemia was mapped to the STSL locus on human chromosome 2p21, and mutations in either of the two genes that comprise this locus, ABCG5 or ABCG8, cause this disease.