Link found between kidney and bowel diseases
Researchers have found six new regions in the human genome that increase susceptibility to immunoglobulin A nephropathy (IgAN), a major cause of kidney failure worldwide. Using genome-wide screening, the scientists identified susceptibility genes in people of Asian and European ancestries that affect both the risk of developing IgAN and the age at which the disease develops. Along with nine previously reported genes, these genetic regions are also associated with the risk of developing inflammatory bowel disease. This observation suggests that IgA nephropathy may be part of a group of autoimmune and inflammatory disorders that share some risk genes.
IgA nephropathy is a kidney disorder that occurs when IgA—a protein that helps the body fight infections—forms aggregates in the kidneys, resulting in inflammation. After many years, the IgA deposits may damage the kidneys, causing them to leak blood and sometimes protein in the urine. Scientists do not know what causes IgA deposits to form in the kidneys; although, as with many common diseases, both genes and environmental factors are likely to play a role. In the current study, the researchers found that several of the genes that confer risk of developing IgA nephropathy may also provide protection against intestinal parasites, which may help explain why respiratory or digestive tract infections seem to be a trigger for IgAN in some individuals.