A sensitive and specific LC-MS/MS method for rapid diagnosis of Niemann-Pick C1 disease from human plasma[S]

• Published in: Journal of lipid research 2011-07, Vol.52 (7), p.1435-1445
• Main Authors: Jiang, Xuntian, Sidhu, Rohini, Porter, Forbes D., Yanjanin, Nicole M., Speak, Anneliese O., te Vruchte, Danielle Taylor, Platt, Frances M., Fujiwara, Hideji, Scherrer, David E., Zhang, Jessie, Dietzen, Dennis J., Schaffer, Jean E., Ory, Daniel S.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Calibration; Case-Control Studies; Child; Child, Preschool; Cholestanols - blood; Cholestanols - chemistry; Cholestanols - isolation & purification; cholesterol; Chromatography, High Pressure Liquid - methods; diagnostic tools; Female; Humans; Infant; Infant, Newborn; Ketocholesterols - blood; Ketocholesterols - chemistry; Ketocholesterols - isolation & purification; liquid chromatography/tandem mass spectrometry; Male; Methods; Middle Aged; neurodegeneration; Niemann-Pick disease; Niemann-Pick Disease, Type C - blood; Niemann-Pick Disease, Type C - diagnosis; oxysterols; Sarcosine - analogs & derivatives; Sarcosine - chemistry; Sensitivity and Specificity; Tandem Mass Spectrometry - methods; Time Factors; Young Adult
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1194/jlr.D015735

Niemann-Pick type C1 (NPC1) disease is a rare, progressively fatal neurodegenerative disease for which there are no FDA-approved therapies. A major barrier to developing new therapies for this disorder has been the lack of a sensitive and noninvasive diagnostic test. Recently, we demonstrated that two cholesterol oxidation products, specifically cholestane-3β,5α,6β-triol (3β,5α,6β-triol) and 7-ketocholesterol (7-KC), were markedly increased in the plasma of human NPC1 subjects, suggesting a role for these oxysterols in diagnosis of NPC1 disease and evaluation of therapeutics in clinical trials. In the present study, we describe the development of a sensitive and specific LC-MS/MS method for quantifying 3β,5α,6β-triol and 7-KC human plasma after derivatization with N,N-dimethylglycine. We show that dimethylglycine derivatization successfully enhanced the ionization and fragmentation of 3β,5α,6β-triol and 7-KC for mass spectrometric detection of the oxysterol species in human plasma. The oxysterol dimethylglycinates were resolved with high sensitivity and selectivity, and enabled accurate quantification of 3β,5α,6β-triol and 7-KC concentrations in human plasma. The LC-MS/MS assay was able to discriminate with high sensitivity and specificity between control and NPC1 subjects, and offers for the first time a noninvasive, rapid, and highly sensitive method for diagnosis of NPC1 disease.