The diagnosis of IgAN was proven by renal biopsy on the basis of granular deposition of IgA in the glomerular mesangium by immunofluorescence detection and the deposition of electron-dense material in the mesangium by ultrastructural examination, in which Henoch–Schonlein purpura, SLE, and chronic hepatic diseases were excluded by detailed clinical and laboratory examinations. Here, CD79A is linked to systemic lupus erythematosus.