While the physiological significance of variable region glycosylation in autoantibodies remains poorly understood, studies show that although total IgG variable-region glycosylation does not differ significantly between active-phase anti-GBM patients and healthy individuals, affinity-purified anti-MPO antibodies exhibit higher variable-region glycosylation than total IgG, whereas anti-GBM antibodies display lower glycosylation, potentially modulating antigen-binding capacity [150]. The gene discussed is MPO; the disease is glioblastoma.