title: Direct analysis of sterols from dried plasma/blood spots by an atmospheric  pressure thermal desorption chemical ionization mass spectrometry  (APTDCI-MS) method for a rapid screening of Smith-Lemli-Opitz  syndrome.
abstract: Here is proposed a rapid and sensitive method involving atmospheric pressure thermal desorption chemical ionization mass spectrometry (APTDCI-MS) for specific laboratory screening of the Smith-Lemli-Opitz syndrome (SLOS), an inherited defect of cholesterol biosynthesis. Biochemical findings in the blood of SLOS patients are low cholesterol (Chol), high 7- and 8-dehydrocholesterol (DHCs) levels and high DHCs/Chol ratios. The APTDCI proposed method is able to ionize sterols for qualitative and quantitative analysis directly from dried plasma/blood spots. Critical APTDCI parameters--desolvation gas flow and temperature--were optimized analyzing Chol, 7-DHC and cholesteryl stearate standards spotted onto a glass slide acquiring the full scan spectra in positive ion mode. Chol levels in dried plasma spots of unaffected controls (n = 23) obtained by the proposed method were compared with those of the enzymatic method (y = 0.9166x + 0.3811; r = 0.8831) while Chol and DHCs of SLOS patients (n = 9) were compared with the gas chromatography flame ionization detection (GC-FID) method (y = 0.8214x + 0.7388; r = 0.8288). The APTDCI-MS method is also able to differentiate normal from SLOS samples directly analyzing whole blood and washed red cells spotted on paper. In conclusion, the intrinsic analytical high-throughput of APTDCI-MS method for sterol analysis could be useful to screen SLO syndrome.
authors.affiliation: Dipartimento di Scienze Biomediche, Facoltà di Medicina e Chirurgia, Università di Foggia, Viale L. Pinto, 1, 71100-Foggia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Paglia
authors.forename: Oceania
authors.initials: O
authors.lastname: D'Apolito
authors.forename: Monica
authors.initials: M
authors.lastname: Gelzo
authors.forename: Antonio
authors.initials: A
authors.lastname: Dello Russo
authors.forename: Gaetano
authors.initials: G
authors.lastname: Corso
mesh_terms: D002775:Cholestadienols / Q000097:blood / Q000737:chemistry; D003684:Dehydrocholesterols / Q000097:blood / Q000737:chemistry; D006801:Humans; D019082:Smith-Lemli-Opitz Syndrome / Q000175:diagnosis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013261:Sterols / Q000097:blood / Q000737:chemistry*
chemical_list: D002775:Cholestadienols; D003684:Dehydrocholesterols; D013261:Sterols; C026359:cholesta-5,8-dien-3 beta-ol; C016705:7-dehydrocholesterol