Immunoglobulin A vasculitis (IgAV), formerly Henoch-Schönlein purpura (HSP), is a small-vessel vasculitis with IgA (immunoglobulin A) immune complex deposition that predominantly affects the skin, joints, kidneys, and gastrointestinal (GI) tract. This evidence concerns the gene CD79A and Henoch-Schoenlein purpura.