Wilson disease is an inherited disorder that causes copper to accumulate in the body's tissues. It primarily affects the liver and brain. Symptoms can include liver disease, neurological or psychiatric issues. It is caused by a genetic defect that prevents the body from properly processing copper. Diagnosis involves tests of copper levels in blood and urine as well as occasionally a liver biopsy. Treatment aims to reduce copper intake and use chelating agents like penicillamine to remove excess copper from the body. With proper treatment, prognosis is good though neurological symptoms may persist in some cases.