Improved analysis of C26:0-lysophosphatidylcholine in dried-blood spots via negative ion mode HPLC-ESI-MS/MS for X-linked adrenoleukodystrophy newborn screening

Abstract

Background: X-linked adrenoleukodystrophy (X-ALD) is the most common human peroxisomal disorder, and is caused by mutations in the peroxisomal transmembrane ALD protein (ALDP, ABCD1). The biochemical defect associated with X-ALD is an accumulation of very long-chain fatty acids (VLCFA, e.g. C24:0 and C26:0), which has been shown to result in the accumulation of C26:0-lysophosphatidylcholine (C26:0-LPC). Methods: We describe the analysis of C26:0-LPC in dried-blood spots (DBS) using a rapid (30. min) and simple extraction procedure, isocratic HPLC resolution of LPC, and structure-specific analysis via negative ion mode tandem mass spectrometry. Results: In putative normal DBS specimens from newborns (N = 223) C26:0-LPC was 0.09 ± 0.03μmol/l whole blood, while in peroxisomal biogenesis disorder (including X-ALD) patients (N = 28) C26:0-LPC was 1.13 ± 0.67μmol/l whole blood. Both multiple reaction monitoring and a neutral loss scan (225.1. Da) analysis of DBS were used to analyze LPC. Conclusions: Compared to a previous report of C26:0-LPC analysis in DBS, the method described here is simpler, faster, and more structure-specific for LPC with C26:0 acyl chains. © 2012.