Wilson disease (WD) is an autosomal recessive disorder, characterized by systemic copper overload, resulting in accumulation of copper in body tissues, especially in the liver and brain. The disease is a manifestation of an excessive absorption of copper from the small intestine and decreased excretion of copper by the liver.
The ATBP7 gene, located on chromosome 13, codes for a P-type ATPase (ATPase, Cu(2+)-Transporting, Beta Polypeptide), which functions in the export of copper out of the cells, such as in the efflux of hepatic copper into the bile, and its incorporation into ceruloplasmin. Mutated copies of the ATPB7 gene result in the production of defective transport protein, which is unable to properly transport copper into the bile. Copper, therefore, builds up in the body tissues causing the toxicity noticed in WD.