PRTN3 and rheumatoid arthritis: To address to which degree IgG Fc sialylation affects human bone architecture, we measured the amount of Fc sialylation, galactosylation and fucosylation of total IgG and disease-specific autoantibodies (ACPA) in 30 patients with rheumatoid arthritis and related these results to bone microstructures of the distal radius measured by micro-computed tomography (μCT).