Delayed-release budesonide is an enteric mucosal B-lymphocyte immunomodulator, which can reduce the production of pathogenic galactose-deficient IgA1 (Gd-IgA1) by inhibiting the number and activity of B-lymphocytes, and treat IgA nephropathy from the source.[6,7] In 2021, delayed-release budesonide received expedited regulatory approval for the treatment of proteinuria in patients with IgA nephropathy and an eGFR > 30 mL/min/1.73 m2,[8] however its efficacy and safety in patients with eGFR < 30 mL/min/1.73 m2 has been less well reported. The gene discussed is IGHA1; the disease is IgA glomerulonephritis.