Human congenital disorders of glycosylation (CDGs) are the result of defects in assembly or processing of the N-glycan moiety of serum glycoproteins and are usually diagnosed by analysis of N-glycosylation of serum transferrin through isoelectric focusing and immunoblotting. However, analysis of the entire array of serum glycoproteins may prove to be a more efficient method of detection since CDGs affect all tissue-derived glycoproteins; a more complete glycan examination could remedy some of the shortcomings of transferrin isoelectric focusing. We sought to develop a highly sensitive and noninvasive mass spectrometric-based method to analyze the structure and composition of N-glycans from total serum glycoproteins. We also sought to facilitate the analysis of archival heel-stick whole blood samples on newborn screening filter paper. N-Glycans in total serum glycoproteins from multiple normal adult volunteers were released by treatment with N-glycanase and processed by their binding to Carbograph cartridges. The glycans were subsequently profiled by matrix-assisted laser desorption/ionization and time-of-flight mass spectrometry (MALDI-TOF-MS). The expected N-glycan structures were found in all donors with a sensitivity of 125 μL of total serum and a high degree of reproducibility. Using similar methodology, we prepared total N-glycans for MALDI-TOF-MS profiling using whole blood spotted on newborn screening filter paper and found reproducible sensitivity with as little as 22.5 μL of blood. The availability of this highly sensitive procedure for analyzing total N-glycan structures using serum or newborn screening filter paper samples and MALDI-TOF-MS may be useful in future studies of infant blood samples for postnatal diagnosis of CDGs. As newborn screening filter paper can be stored indefinitely under the proper conditions, this method could also allow testing of archival samples for CDGs.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.