Abstract:
:Smith-Lemli-Opitz syndrome (SLOS) is a genetic disorder characterized by low plasma cholesterol and high 7-dehydrocholesterol (7-DHC). Synthesis of cholesterol and 7-DHC and its metabolites is regulated by HMG-CoA reductase, whose activity can be measured by 24-h excretion of its product mevalonate. We devised a simple, non-invasive method for collecting 24-h urine in our subjects. With a background of a very low cholesterol diet, mean mevalonate excretion did not differ between controls and SLOS children, indicating that SLOS subjects have normal HMG-CoA reductase activity. In a short term feeding study, the effects of a high cholesterol diet in SLOS subjects include a significant 55% increase in plasma cholesterol levels and 39% decrease in mevalonate excretion and no change in plasma 7-DHC levels. However, in four SLOS subjects, fed a high cholesterol diet for 2-3 years, plasma cholesterol levels continued to increase, urinary mevalonate excretion remained low and total 7-DHC decreased significantly, likely from decreased total sterol synthesis. Thus, in SLOS subjects, HMG-CoA reductase activity was normal and was subject to normal cholesterol induced feedback inhibition. However, total sterol synthesis in SLOS may still be decreased because of increased diversion of mevalonate into the shunt pathway away from sterol synthesis.
journal_name
J Lipid Resjournal_title
Journal of lipid researchauthors
Pappu AS,Steiner RD,Connor SL,Flavell DP,Lin DS,Hatcher L,Illingworth DR,Connor WEdoi
10.1194/jlr.m200163-jlr200keywords:
subject
Has Abstractpub_date
2002-10-01 00:00:00pages
1661-9issue
10eissn
0022-2275issn
1539-7262journal_volume
43pub_type
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journal_title:Journal of lipid research
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journal_title:Journal of lipid research
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