Causes of Immunoglobulin A (IgA) Nephropathy
Scientists think that IgA nephropathy is an autoimmune kidney disease, meaning that the disease is due to the body’s immune system harming the kidneys.

People with IgA nephropathy have an increased blood level of IgA that contains less of a special sugar, galactose, than normal. This galactose-deficient IgA is considered "foreign" by other antibodies circulating in the blood. As a result, these other antibodies attach to the galactose-deficient IgA and form a clump. This clump is also called an immune complex. Some of the clumps become stuck in the glomerulus of the nephron and cause inflammation and damage.

For some people, IgA nephropathy runs in families. Scientists have recently found several genetic markers that may play a role in the development of the disease. IgA nephropathy may also be related to respiratory or intestinal infections and the immune system’s response to these infections.