Diagnosis of Smith-Lemli-Opitz syndrome from stored filter paper blood specimens

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Abstract
BACKGROUND Smith–Lemli–Opitz (SLO) syndrome is a recessively inheritable metabolic disease with deficiency of cholesterol and accumulation of dehydrocholesterols, caused by a defect in the last step of cholesterol biosynthesis. Biochemical methods for identification of affected individuals, even prenatally, have been developed. Reliable genetic counselling is now possible. AIM To find a method of proving or disproving whether a child in whom SLO syndrome had been suspected but not confirmed during lifetime had in fact died of the SLO syndrome. METHODS Lipid extracts of stored filter paper blood specimens collected at the national neonatal metabolic screening were used. The ratio of dehydrocholesterols to cholesterol was measured by combined gas chromatography–mass spectrometry. RESULTS The ratio of 8-dehydrocholesterol to cholesterol in stored filter paper specimens clearly distinguished affected infants from normal infants. SLO syndrome was thus proven in two children who had died more than seven years earlier. CONCLUSION It is possible to diagnose SLO syndrome from dried paper specimens, even when the samples were collected more than a decade ago. Genetic counselling is available for families of affected children who died before the discovery of the defect in cholesterol synthesis.