Correlation of Lyso-Gb3 levels in dried blood spots and sera from patients with classic and Later-Onset Fabry disease

Background: Fabry disease (FD), an X-linked lysosomal storage disorder, results from the deficient activity of alpha-galactosidase A (a-Gal A) and the accumulation of its substrates, globotriaosylceramide (Gb3) and its deacylated derivative, globotriaosyl-sphingosine (Lyso-Gb3). Here, we compared the levels of Lyso-Gb3 in dried blood spots (DBS) and sera in affected males and heterozygotes with the "Classic" and "Later-Onset" phenotypes. Methods: The Lyso-Gb3 concentrations in DBS and sera from 56 FD patients were determined by highly sensitive electrospray ionization liquid chromatography tandem mass spectrometry. Results: The serum Lyso-Gb3 levels in 18 and 5 affected males with the Classic and Later-Onset phenotypes, were 61 +/- 38 and 14 +/- 12 ng/mL, respectively. Lyso-Gb3 levels in 30 females from Classic families and three females from Later-Onset families were 10 +/- 5.4 and 2.4 +/- 1.0 ng/mL, respectively. The linear regression model with serum Lyso-Gb3 as the dependent variable and DBS Lyso-Gb3 an independent variable was described by the function y = -1.83 + 1.68 * x and showed a high coefficient of determination, R-2 = 0.976. T Conclusion: DBS provides a convenient, sensitive, and reproducible source to measure Lyso-Gb3 levels for diagnosis, initial phenotypic assignment, and therapeutic monitoring in patients with Fabry disease. (C) 2017 Elsevier Inc. All rights reserved.