> Wilson disease (WND) is a disorder of copper transport resulting in copper accumulation in liver, kidney, and brain. This recessive disorder expresses variable clinical symptoms affecting liver, brain, and/or kidney. The age of onset of symptoms varies from 3 to almost 70 years, so the diagnosis for this treatable disorder is easily missed. The defective gene is a membrane P-type ATPase, with similar structure to the other metal transporting ATPases. Most patients with Wilson disease are compound heterozygotes. This report describes the database we have developed for reporting of mutations in ATP7B , the gene defective in WND. The database includes more than 518 variants (379 probable disease-causing and the remainder possible normal variants) from populations worldwide (Available at: www.medicalgenetics.med.ualberta.ca/wilson/index.php ; Last accessed: 20 June 2007). The tables in this database are a valuable resource for the study of population variation and the function of the transporter, and will assist in the identification of disease and non-disease-causing sequence variants. Hum Mutat 28(12), 1171–1177, 2007. © 2007 Wiley-Liss, Inc.

Wilson disease is an autosomal recessive disorder of copper metabolism. The gene for this disorder has been cloned and identified to encode a copper-transporting ATPase (ATP7B), a member of a large family of cation transporters, the P-type ATPases. In addition to the core elements common to all P-type ATPases, the Wilson copper-transporting ATPase has a large cytoplasmic N-terminus comprised six heavy metal associated (HMA) domains, each of which contains the copper-binding sequence motif GMT/HCXXC. Extensive studies addressing the functional, regulatory, and structural aspects of heavy metal transport by heavy metal transporters in general, have offered great insights into copper transport by Wilson copper-transporting ATPase. The findings from these studies have been used together with homology modeling of the Wilson disease copper-transporting ATPases based on the X-ray structure of the sarcoplasmic reticulum (SR) calcium-ATPase, to present a hypothetical model of the mechanism of copper transport by copper-transporting ATPases.

Copper transporting P-type ATPases, designated ATP7A and ATP7B, play an essential role in mammalian copper balance. Impaired intestinal transport of copper, resulting from mutations in the ATP7A gene, lead to Menkes disease in humans. Defects in a similar gene, the copper transporting ATPase ATP7B , result in Wilson disease. This ATP7B transporter has two functions: transport of copper into the plasma protein ceruloplasmin, and elimination of copper through the bile. Variants of ATP7B can be functionally assayed to identify defects in each of these functions. Tissue expression studies of the copper ATPases and their copper chaperone ATOX1 indicate that there is not complete overlap in expression. Other chaperones may be important for the transport of copper into ATP7A and ATP7B.

Wilson disease (WD) is an autosomal recessive inherited disorder of copper metabolism, resulting in pathological accumulation of copper in many organs and tissues. The hallmarks of the disease are the presence of liver disease, neurologic symptoms, and Kayser–Fleischer corneal rings. The leading neurologic symptoms in WD are dysathria, dyspraxia, ataxia, and Parkinsonian-like extrapyramidal signs. Changes in the basal ganglia in brain magnetic resonance imaging (MRI) are characteristic features of the disease. In presence of liver cirrhosis, some features may resemble hepatic encephalopathy. Symptoms and MRI abnormalities may be fully reversible on treatment with zinc or copper chelators. Improvement can be monitored by serial recording of brain-stem-evoked responses. The basic defect is an impaired traficking of copper in hepatocytes. ATP7B is the gene product of the WD gene located on chromosome 13 and resides in hepatocytes in the trans-Golgi network, transporting copper into the secretory pathway for incorporation into apoceruloplasmin and excretion into the bile. While about 40% of patients preset with neurologic symptoms, little is known about the role of copper and ATP7B in the central nervous system. In some brain areas, like in the pineal gland, ATP7B is expressed and functionally active. Increasing evidence supports an important role for metals in neurobiology. Two proteins related to neurodegeneration are copper-binding proteins (1) the amyloid precursor protein (APP), a protein related to Alzheimer's disease, and (2) the Prion protein, related to Creutzfeldt–Jakob disease. A major source of free-radical production in the brain derives from copper. To prevent metal-mediated oxidative stress, cells have evolved complex metal transport systems. APP is a major regulator of neuronal copper homeostasis and has a copper-binding domain (CuBD). The surface location of this site, structural homology of CuBD to copper chaperones, and the role of APP in neuronal copper homeostasis are consistent with the CuBD acting as a neuronal metallotransporter. There are several copper-containing enzymes in the brain, like dopamine beta hydroxylase or Cu/Zn superoxide dismutase (SOD1). Their function may be altered because of copper overload. WD appears to be associated with a dopaminergic deficit. Mutations in the SOD1 gene cause familial amyotrophic lateral sclerosis. Survival of transgenic mice with a mutant SOD1 which fails to incorporate Cu( 2+ ) in its active site was improved by copper depletion. Wilson disease (WD) is an autosomal recessive inherited disorder in which copper pathologically accumulates primarily within the liver and subsequently in the neurologic system and many other organs and tissues. Presence of liver disease, neurologic symptoms, and Kayser–Fleischer corneal rings are the hallmarks of the disease.

Abstract Wilson disease is an inherited, autosomal recessive, copper accumulation and toxicity disorder that affects about 30 individuals per million. This rare disease is caused by mutations in the gene encoding a copper-transporting P-type ATPase, which is important for copper excretion into bile, leading to copper accumulation in the liver. Toxic copper concentrations can also be found in the brain and kidney, and clinical phenotypes include hepatic, haemolytic, neurologic and psychiatric diseases. Diagnosis is based on the combination of clinical features and findings such as increased urinary copper excretion, reduced levels of serum ceruloplasmin, high concentrations of copper in liver tissues and Kayser–Fleischer rings. Genetic studies are also becoming available for clinical use, but the utility of direct mutation analysis is limited. Wilson disease can be treated, and early diagnosis is essential: the goal of therapy is to reduce copper accumulation either by enhancing its urinary excretion or by decreasing its intestinal absorption. Medical therapies include penicillamine, trientine, zinc and tetrathiomolibdate. Liver transplantation is a relatively successful treatment option when medical therapy fails or in case of acute liver failure, even though it is also characterized by short- and long-term complications.