A rare autosomal recessive disease characterized by the deposition of copper in the brain; LIVER; cornea; and other organs. It is caused by defects in the ATP7B gene encoding copper-transporting ATPase 2 (EC 3.6.3.4), also known as the Wilson disease protein. The overload of copper inevitably leads to progressive liver and neurological dysfunction such as liver cirrhosis; tremor; ataxia and intellectual deterioration. Hepatic dysfunction may precede neurologic dysfunction by several years.