Screening for abnormal cholesterol biosynthesis in the Smith-Lemli-Opitz syndrome: Rapid determination of plasma 7-dehydrocholesterol by ultraviolet spectrometry
✍ Scribed by Honda, Akira; Batta, Ashok K.; Salen, Gerald; Tint, G. Stephen; Chen, Thomas S.; Shefer, Sarah
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 155 KB
- Volume
- 68
- Category
- Article
- ISSN
- 0148-7299
No coin nor oath required. For personal study only.
✦ Synopsis
The Smith-Lemli-Opitz syndrome (SLOS) is a common condition caused by deficiency of 7-dehydrocholesterol ⌬ 7 -reductase. The syndrome can usually be diagnosed by demonstrating markedly increased plasma concentrations of the cholesterol precursor, 7-dehydrocholesterol. We describe a simple and rapid method for detection of plasma 7dehydrocholesterol by use of ultraviolet (UV) spectrometry. Lipids were extracted from plasma by addition of ethanol and n-hexane, and the n-hexane phase was directly subjected to spectrometry. The absorption maxima characteristics of 7-dehydrocholesterol ( max 271, 282, and 294 nm) were observed in patients' plasma but not in controls. For quantitative measurements, absorbance at 282 nm was used. Since this absorbance is the sum of the absorbance derived from 7-dehydrocholesterol and background absorbance, the concentrations of 7dehydrocholesterol in various plasma samples were quantified by subtracting estimated background absorbance at 282 nm from observed absorbance at 282 nm. The results correlated well with total (free plus esterified) 7-dehydrocholesterol concentrations measured by gas-liquid chromatographic method. The UV spectrometric assay was sensitive enough to detect increased 7-dehydrocholesterol in cultured skin fibroblasts from patients grown in delipidated medium. The present method will make it possible to screen plasma or fibroblasts to detect the syndrome rapidly in general clinical laboratories.