In a mass spectrometry study, the number of galactose/hinge-part residues in serum IgA was significantly decreased in patients with IgAN compared to patients with Crohn’s disease and ulcerative colitis, suggesting that the glycosylation pattern of GALT-derived IgA is different from that of circulating nephropathogenic IgA [71]. Here, CD79A is linked to ulcerative colitis.