What are the genetic changes related to primary sclerosing cholangitis ?
Primary sclerosing cholangitis is thought to arise from a combination of genetic and environmental factors. Researchers believe that genetic changes play a role in this condition because it often occurs in several members of a family and because immediate family members of someone with primary sclerosing cholangitis have an increased risk of developing the condition. It is likely that specific genetic variations increase a person's risk of developing primary sclerosing cholangitis, and then exposure to certain environmental factors triggers the disorder. However, the genetic changes that increase susceptibility and the environmental triggers remain unclear.  There is evidence that variations in certain genes involved in immune function influence the risk of developing primary sclerosing cholangitis. The most commonly associated genes belong to a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). Each HLA gene has many different normal variations, allowing each person's immune system to react to a wide range of foreign proteins. Specific variations of several HLA genes seem to be present more often in people with primary sclerosing cholangitis than in people who do not have the disorder. These variations may dysregulate the body's immune response, leading to the inflammation of the bile ducts in people with primary sclerosing cholangitis. However, the mechanism is not well understood. Researchers are also studying variations in other genes related to the body's immune function to understand how they contribute to the risk of developing this condition.