Brandt AU, Sy M, Bellmann-Strobl J, et al. - Researchers conducted this cross-sectional study to examine a marker of endogenous serum N-acetylglucosamine (GlcNAc) levels in patients with multiple sclerosis (MS). The discovery study selected 54 MS patients from an outpatient clinic as well as 66 healthy controls (38 women; mean [SD] age, 42 [20] years) between April 20, 2010, and June 21, 2013, whereas the confirmatory study enlisted 180 MS patients from screening visits at an academic MS study center between April 9, 2007, and February 29, 2016. This research suggests that deficiency of GlcNAc plus its stereoisomers (HexNAc) could be a biomarker for progressive MS. Previous preclinical, human genetic, and ex vivo human mechanistic studies showed that N-glycan branching and/or GlcNAc may decrease proinflammatory responses, promote myelin repair, and decrease neurodegeneration. The findings suggest that GlcNAc deficiency may be linked to progressive disease and neurodegeneration in MS patients.