766 (2002) 365–370 Journal of Chromatography B, www.elsevier.com / locate / chromb Short communication Effects of sample storage on 7- and 8-dehydrocholesterol levels analysed on whole blood spots by gas chromatography–mass spectrometry-selected ion monitoring a b b a Gaetano Corso , Massimiliano Rossi , Daniele De Brasi , Immacolata Rossi , b a, * Giancarlo Parenti , Antonio Dello Russo a ` Dipartimento di Biochimica e Biotecnologie Mediche, Universita di Napoli Federico II, Via S. Pansini 5, 80131 Naples, Italy b ` Dipartimento di Pediatria, Universita di Napoli Federico II, Via S. Pansini 5, 80131 Naples, Italy Received 13 July 2001; received in revised form 16 October 2001; accepted 19 October 2001 Abstract Smith–Lemli–Opitz syndrome (SLOS) patients have increased 7- and 8-dehydrocholesterol (DHC) concentrations. Using gas chromatography–mass spectrometry with selected ion monitoring we investigated whether storage time (24 h, 7 and 30 days, and 22 months at room temperature or at 48C) affected DHC concentrations in whole blood spots (WBSs) from SLOS patients and normal controls. Our results suggest that WBS sterol analysis can be used for SLOS screening and possibly related inborn errors of sterol metabolism with a 100% sensitivity and specificity on specimens stored for up to 30 days, either at room temperature or 48C. After 22 months of storage at both temperature SLOS samples can be indistinguishable from control samples. Therefore, great caution should be used to exclude SLOS by sterol analysis of WBSs stored for a long time.  2002 Elsevier Science B.V. All rights reserved. Keywords: Dehydrocholesterol 1. Introduction continuum from the severe ‘‘type 2’’ SLOS to the milder ‘‘type 1’’ form [2]. Smith–Lemli–Opitz syndrome (SLOS) is a multi- SLOS is a dysmorphic syndrome characterized by ple congenital anomalies-mental retardation syn- major malformations due to a single biochemical drome, characterised by delayed psychomotor de- defect. In 1994 Tint et al. [3] demonstrated that 7 velopment, failure to thrive, typical facies, limb SLOS results from deficiency of D -dehydrocholes- malformations, incomplete development of male terol reductase (DHCR), the enzyme that catalyses genitalia and possible association of internal organ the last step of cholesterol biosynthesis. SLOS anomalies [1]. These signs are variably associated patients typically have low cholesterol levels and and the disease phenotype represents a clinical increased 7- and 8-dehydrocholesterol (DHC) con- centrations. Recently, the DHCR-encoding gene has been cloned and several mutations have been iden- *Corresponding author. Tel.: 139-081-7463-115; fax: 139- tified in SLOS patients [4–6]. Interestingly, high 081-7463-653. E-mail address: dellorus@unina.it (A. Dello Russo). levels of 8-DHC have been reported in Conradi– 1570-0232 / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0378-4347(01)00520-5