Although a renal biopsy was performed because of a suspicion of renal sarcoidosis, contrary to our expectations, it showed IgA nephropathy without granulomatous interstitial nephritis and noncaseating granulomas, no findings suggestive of sarcoidosis, and glomerular Gd-IgA1 was clearly stained in the mesangial area. The gene discussed is IGHA1; the disease is IgA glomerulonephritis.