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Wilson's Disease |
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Wilson's disease or lentigohepatic degeneration is an autosomal recessive hereditary disease, with an incidence of about 1 in 30,000. Its main feature is accumulation of copper in tissues, which manifests itself with neurological symptoms and liver disease. The estimated heterozygous carrier rate is about 1 in 90, meaning that 1 in 90 people are unaffected carriers of this mutation. The disease affects men and women equally and occurs in all races.
Description
The Wilson's disease gene (WND) has been mapped to chromosome 13 (13q14.3) and is expressed primarily in the liver, kidney, and placenta but has also been found in the heart, brain, and lung, albeit at much lower levels. The gene codes for a P-type ATPase that transports copper into bile and incorporates it into ceruloplasmin. Bile is a liquid produced by the liver that helps with digestion.
The mutant form of WND expressed in people with Wilson's disease inhibits the release of copper into bile. As the excretion of copper from the body is thus impaired, the copper builds up in the liver and injures liver tissue. Eventually, the damage causes the liver to release the copper directly into the bloodstream, which carries the copper throughout the body. The copper buildup leads to damage in the kidneys, brain, and eyes. If not treated, Wilson's disease can cause severe brain damage, liver failure, and death.
Clinical features
Clinical symptoms rarely develop before 5 years of age, despite the biochemical defect being present at birth. The average concentration of hepatic copper may reach 20 times normal levels, whilst plasma ceruloplasmin levels are typically less than 30% of normal.
The age of presentation seems to correlate with the organ system involved. About half (40-50%) of patients first present with hepatic symptoms and half (40-50%) with neurologic symptoms. The average age for hepatic symptoms is 10-14 years, compared with 19-22 years for neurologic symptoms. Patients rarely present after age 40.
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