Both glomerular IgA and Gd-IgA1 findings were negative in patients with idiopathic nephrotic syndrome (n = 5), MPGN (n = 1), membranous nephropathy (n = 1), oligomeganephronia (n = 1), Alport syndrome (n = 1), C3 glomerulonephritis (n = 1), poststreptococcal acute glomerulonephritis (n = 1), and hemolytic uremic syndrome (n = 1). Here, IGHA1 is linked to primary membranoproliferative glomerulonephritis.