Wilson's disease, also called hepatolenticular degeneration, is a rare inherited condition that causes copper to build up in the body, especially in the liver, brain and eyes. Symptoms most often appear between ages 3 and 40. But they can appear at any time. Copper is important for healthy nerves, bones, collagen and the skin pigment melanin. You usually take in copper from the food you eat. Your liver creates a substance called bile that removes any extra copper. In people with Wilson's disease, copper isn't removed properly and instead builds up. If not treated, this can sometimes become life-threatening. When diagnosed early, Wilson's disease is treatable. Many people with the condition live full lives. Wilson's disease affects about 1 in 30,000 people worldwide. There are other conditions that affect how the body processes copper. But Wilson's disease is caused by changes, also called mutations, in a specific gene - ATP7B.