A mass spectrometric strategy for profiling glycoproteinoses, Pompe disease, and sialic acid storage diseases

Abstract

Glycoproteinoses, Pompe disease, and sialic acid storage diseases are characterized by a massive accumulation of unprocessed oligosaccharides and/or glycoconjugates in urine. The identification of these glycocompounds is essential for a proper diagnosis. In this study, we investigated the potential of MALDI-TOF-MS to identify glycocompounds present in urine from patients with different inborn errors of glycan metabolism. Urinary glycocompounds were permethylated, and analyzed using GC-MS and MALDI-TOF-MS. In order to confirm tentative assignments, a second aliquot of urine was purified on a C18 Sep-Pak cartridge and glycocompounds were desalted on a column of nonporous graphitized carbon. The glycocompounds were then sequentially on-plate digested using an array of exoglycosidases. A range of disease-specific oligosaccharides as well as glycopeptides was identified for all oligosacchariduria models. In addition, free sialic acid accumulated in urine from a patient suffering from French-type sialuria, has been detected by a GC-MS approach, which could be applied to other sialic acid storage diseases. This procedure is simple, and can be performed in few simple steps in less than 24 h. This current method can be applied for newborn screening for other inherited metabolic diseases as well as for assessing treatments in clinical trials.

Fast urinary screening of oligosaccharidoses by MALDI-TOF/TOF mass spectrometry

“…Indeed, it has previously been reported in chemically derivated urine (e.g. permethylated urines) that some oligosaccharides can be detected by mass spectrometry [30,41]. In our study, we found in urines from healthy subjects, with a similar abundant pattern, a set of intensive peaks for which no chemical composition could be identified.…”

“…Efforts to improve the oligosaccharidosis screening have been achieved using mass spectrometry. For instance, the group of Michalski developed a strategy combining three different approaches with MALDI-TOF-MS and GC-MS after permethylation and enzymatic digestions to identify the glycocompounds accumulated in urine [30]. More recently, a method using PMP derivatization combined with LC-MS/MS has been adapted to screen oligosaccharidoses by selected reaction monitoring MS, and it revealed specific patterns corresponding to each disorder [32].…”

“…Urine is known to contain some simple oligosaccharides but their excretion levels depend on various physiological circumstances [30]. Indeed, it has previously been reported in chemically derivated urine (e.g.…”

“…Different MS approaches have been described for oligosaccharidosis screening. However, to the best of our knowledge, these methods necessitate prior treatment of the urinary samples with derivatization such as permethylation or PMP (3-methyl-1-phenyl-2-pyrazolin-5-one) processes usually combined with HPLC or GC and confirmed by enzymatic digestion [3,30-32]. Although derivatization procedures bring improvements in sensitivity, these methods add procedures with possible sample deterioration and contamination, thereby potentially decreasing their benefits.…”

Analysis of carbohydrates and glycoconjugates by matrix‐assisted laser desorption/ionization mass spectrometry: An update for 2007–2008

“…Patient report. Many truncated complex glycans lacking galactose and sialic acid (Nsibu, et al, 2008) Various Urinary glycans TOF (DHB), glycans (per-Me), GC/MS Development of method for profiling glycoproteinoses (Faid, et al, 2008) Unspecified Urine Q-TOF (THAP, NH 4 citrate), Glycans…”