What is Kidney IgA Nephropathy? One of the most common forms of kidney disease in the world is IgA Nephropathy.  This disease occurs when deposits of Immunoglobulin A build up in the kidneys.  These are a normal part of the immune system that helps your body get rid of infections.  People with Kidney IgA Nephropathy have a defective version of immunoglobulin A.  The...