Accurate detection of Smith–Lemli–Opitz syndrome carriers by measurement of the rate of reduction of the ergosterol C-7 double bond in cultured skin fibroblasts

摘要: The activity of ergosterol Δ7-reductase (3β-hydroxysteroid Δ7-reductase) was measured in cultured skin fibroblasts from 7 controls, 10 Smith–Lemli–Opitz syndrome (SLOS) patients, and parents (obligate carriers). were exposed to delipidated medium supplemented with lovastatin for 24h the enzyme determined by incubating cell-free homogenate (ergosta-5,7,22-trien-3β-ol) measuring mass brassicasterol (ergosta-5,22-dien-3β-ol) formed gas chromatography–mass spectrometry selected-ion monitoring. In carriers, significantly lower than controls (22±2 vs 65±10 pmol/min per mg protein, p<0.0005), no overlap observed. mean carriers' more 100 times higher patients' cells (0.2 protein). use avoids many problems caused instability lack availability radiolabelled 7-dehydrocholesterol. present method makes it possible discriminate SLOS carriers both patients using a commercially available substrate common analytical equipment.