Wilson's disease or also known as hepatolenticular degeneration is a hereditary autosomal reccessive disease. The incidence rate of this condition in most parts of the world is about 1 in 30,000 with the preponderance among males. Its main characteristic feature is accumulation of the mineral copper in tissues, which manifests as neurological symptoms and liver disorder. The symptoms of Wilson’s disease typically appear around 18 to 21 years of age but sometimes not until 30 years old. Rarely, the onset of symptoms may appear at age 50 and even beyond.
The age of clinical onset of symptoms correlates well with the organ system involved. Almost half (40–50%) the patients first present with hepatic or liver symptoms and the other half (40–50%) with neurologic symptoms. The hepatic symptoms usually appear at average age of 10 to 14 years which is relatively earlier than those with neurologic symptoms which appear at around 19 to 22 years of age.
The Wilson's disease gene (WND) has been found to be present at chromosome 13 (13q14.3) and is expressed primarily in the liver, kidney, and placenta but has also been found at much lower levels in the heart, brain, and lung The gene codes for a P-type ATPase which is responsible for transporting copper into bile and incorporating it into ceruloplasmin.
Patients with Wilson’s disease expressed the mutant form of WND which inhibits the release of copper into bile. Therefore, copper excretion from the body is widely impaired. As a result, copper builds up in the liver and damages the liver tissue. Eventually, copper is released directly into the bloodstream, carrying the copper now all throughout the body. Massive copper buildup can damage the kidneys, brain, and eyes hence; if left untreated, Wilson's disease can finally cause severe brain damage, hepatic failure, and even death. When copper deposits in the basal ganglia (part of the brain responsible for movement), specifically in the putamen and globus pallidus (collectively called the lenticular nucleus), death of the cells may ensue , producing symptoms similar to Parkinson's disease.
As mentioned earlier, the main features are liver and neuropsychiatric problems. The most common hepatic presentation is chronic active hepatitis that may culminate in liver cirrhosis (also known as Laennec cirrhosis or Hepato-portal cirrhosis). A fulminant liver failure may occur in some patients; this is characterized by markedly low levels of alkaline phosphatase with elevated bilirubin levels. An incidence of hepatocellular carcinoma otherwise known as hepatoma, a malignant liver disease may surprisingly present but rarely. The following are some of the neuropsychiatric symptoms that a patient may manifest : early dementia, mood disorders or psychosis and signs of asterixis (a flapping tremor of the hands which is a sign of hepatic failure) and parkinsonism (e.g. ataxia, dyskinesia, tremors, and rigidity).
A screening test commonly performed to detect patients with liver disorder due to Wilson’s disease is determining the level of ceruloplasmin. A low level of ceruloplasmin is present in over 80% of patients with Wilson’s disease. A more accurate measurement is obtaining a 24 hour urine specimen or a blood test to directly measure the copper levels. Copper levels may likewise be tested in the sample obtained by liver biopsy. The average hepatic copper concentration may be up to 20 times the normal levels, while the levels of plasma ceruloplasmin are generally less than 30% of normal.
Lifelong use of chelating agents such as D-penicillamine or trientine hydrochloride, which are medications that help remove copper from tissues are the mainstay of treatment. Patients also need to follow a low-copper diet which means avoiding the following foods: mushrooms, nuts, chocolate, dried fruits, liver, and shellfish. Taking vitamin B6 is needed aside from extra zinc (help in blocking the absorption of copper from the small intestines) intake.
In patients with fulminant cases of Wilson’s disease that fails to respond to the usual standard treatment, liver transplantation is effective. Due to the fact that the primary defect resides within the liver itself, transplantation is curative but it is only performed in severely ill patients so, still the prognosis is not quite good.
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