IgA nephropathy (Berger's disease) is a form of mesangial proliferative nephritis. Structures in the kidney called glomeruli become inflamed, and a type of antibody called IgA deposits in the kidney. The disorder can appear as acute, rapidly progressive, or chronic glomerulonephritis, or as visible or microscopic blood in the urine. IgA nephropathy usually is discovered after one or more episodes of dark or bloody urine in a person with no other symptoms of kidney disorder. Bloody urine may begin during or soon after a respiratory infection. Acute nephritic syndrome or nephrotic syndrome (groups of symptoms associated with decreased kidney functioning) may result. Risk factors include having a personal or family history of IgA nephropathy or Henoch Schonlein purpura (a form of vasculitis that affects many parts of the body, and may cause a kidney lesion that is identical to the lesion of Berger's disease). IgA nephropathy can occur in persons of all ages, but most often affects males in their teens to late 30s.
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