IgA nephropathy is a kidney disorder that occurs when IgA (immunoglobulin A), a protein that helps the body fight infections, settles in the kidneys. In the early stages, IgA nephropathy has no symptoms. The first sign of this condition may be blood in the urine. End-stage kidney disease may develop. In most instances, the cause of this condition is unknown; however, certain disorders have been linked with IgA nephropathy, such as cirrhosis of the liver, celiac disease, and HIV infection. Although IgA nephropathy usually occurs in a family with no other affected members, several cases of familial IgA nephropathy have been reported. Familial IgA nephropathy is suspected to run through families in an autosomal dominant manner and is linked to genetic material on the long arm of chromosome 6 (6q22-23).