CD79A and IgA glomerulonephritis: Closely related to IgA nephropathy is another clinical entity called Henoch Schonlein Purpura (HSP), an IgA-mediated systemic small-vessel vasculitis that, in addition to the kidneys, affects the skin (purpura), joints (arthritis), gut (melena, abdominal pain), etc.8,9 The definitive diagnosis of both can only be made on biopsy and the main distinction between the two is the extra-renal involvement seen in HSP.2