Wilson's disease can manifest with symptoms of liver disease or neuropsychiatric disorders in children and adults. This autosomal recessive disorder is caused by a copper metabolism disorder due to a mutation in the ATP7B transporter. Excessive amounts of copper accumulate in the body due to inhibition of the release of copper into bile. Because effective treatment is available, recognizing this disease in presymptomatic or early stages, when it can be reversed, is highly important. Diagnosis is often easy but the available tests (measurement of ceruloplasmin, and blood, urinary and liver copper levels) can be misleading. There is no single test with 100% sensitivity in screening nor do any of the tests, when used alone, provide 100% specificity. Diagnosis is currently based on the combination of clinical findings and the results of laboratory tests. Genetic study, with a finding of mutations in the two alleles of the ATP7B gene, is still not a rapid and easily available alternative and the absence of these mutations does not rule out the possible presence of other mutations not yet described.