Human galactose-deficient IgA1 (Gd-IgA1) is associated with the pathogenesis of IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN, Henoch–Schönlein purpura).[6] We report a patient with metastatic rectal cancer treated with bevacizumab who developed hematuria, nephrotic syndrome, and purpura with IgAVN, as was established by Gd-IgA1. The gene discussed is IGHA1; the disease is nephrotic syndrome.