What Is Wilson's Disease?

Genetic disorder causes harmful accumulation of copper

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Wilson’s disease, also known as hepatolenticular degeneration, is a genetic disorder which results in the excessive accumulation of copper in the body. It’s an uncommon disorder affecting one in every 30,000 people. For a person to be affected, he or she must inherit a specific genetic mutation from not one but both parents.

This abnormal accumulation of copper most predominately affects the liver, brain, kidney, and eyes but may also impact the heart and endocrine system.

Symptoms of Wilson’s disease tend to manifest rather early in life, typically between the ages of five and 35. Complications of the disease can include liver failure, kidney problems, and sometimes serious neuropsychiatric symptoms.

Causes

Wilson’s disease is an inherited disorder in the autosomal recessive pattern. What this means is that both parents much be carriers for the genetic mutation, although neither will likely have symptoms nor a family history of the disease. Persons who are carriers may have evidence of abnormal copper metabolism but usually not enough to warrant medical intervention.

Wilson’s disease is one of several genetic disorders in which copper abnormally builds up in the system, most often in the liver. It involves a gene called the ATP7B which the body uses to secrete copper into bile. The mutation of this gene prevents this process and interferes with the excretion of copper from the body.

As the levels of copper begin to overwhelm the liver, the body will try to break them down by secreting hydrochloric acid and ferrous iron to oxidize the copper molecules. Over time, this reaction can cause liver scarring (fibrosis), hepatitis, and cirrhosis.

Because copper is central to both the formation of collagen and the absorption of iron, any impairment of this process can cause injury at an early age.

This is why Wilson’s disease can cause hepatitis in the first three years of life and cirrhosis (a condition most commonly associated with older adults) in adolescents and young adults.

Liver-Related Symptoms

The symptoms of Wilson’s disease vary by the location of the tissue damage. Since copper tends to accumulate in the liver and brain first, the symptoms of the disease often appear most profoundly in these organ systems.

Early symptoms of liver dysfunction are often similar to those seen with hepatitis. The progressive development of fibrosis can lead to a condition known as portal hypertension in which the blood pressure within the liver begins to rise. As the damage to the liver increases, a person may experience a spectrum of serious and potentially life-threatening events, including internal bleeding and liver failure.

Among the more common liver-related symptoms seen in Wilson’s disease:

  • Fatigue
  • Nausea
  • Vomiting
  • Loss of appetite
  • Muscle cramps
  • Yellowing of the skin and eyes (jaundice)
  • Accumulated fluid in the legs (edema)
  • Accumulation of fluid in the abdomen (ascites)
  • Spider web-like veining on the skin (spider angiomas)
  • Pain or fullness in the upper left abdomen due to an enlarged spleen

While cirrhosis commonly occurs in persons with severe, untreated Wilson’s disease, it rarely advances to liver cancer (unlike cirrhosis associated with either viral hepatitis or alcoholism).

Neurological Symptoms

Acute liver failure is characterized by the development of a form of anemia called hemolytic anemia in which red blood cells will literally rupture and die. Since red blood cells contain three times the amount of ammonia as plasma (the liquid component of blood), the destruction of these cells can cause the rapid buildup of ammonia and other toxins in the blood stream.

When these substances irritate the brain, a person may develop hepatic encephalopathy, the loss of brain function due to liver disease. Symptoms may include:

  • Migraines
  • Insomnia
  • Memory loss
  • Slurred speech
  • Changes in vision
  • Mobility problems and loss of balance
  • Anxiety or depression
  • Personality changes (including impulsivity and impaired judgment)
  • Parkinsonism (rigidity, tremors, slowed movement)
  • Psychosis

Because the potential causes of these symptoms are vast, Wilson’s disease is rarely diagnosed on neuropsychiatric features alone.

Other Symptoms

The abnormal accumulation of copper in the body can directly and indirectly affect other organ systems, as well.

  • When occurring within the eyes, Wilson’s disease can cause a characteristic symptom known as Kayser-Fleisher rings. These are bands of golden-brown discoloration around the perimeter of the iris caused by deposits of excess copper. It occurs in around 65 percent of people with Wilson’s disease. 
  • When occurring in the kidneys, Wilson’s disease can cause fatigue, muscle weakness, confusion, kidney stones, and blood in urine due to excess acids in the blood. The condition can also cause the excessive deposit of calcium in the kidneys and, paradoxically, the weakening of bones due to the redistribution and loss of calcium.

While uncommon, Wilson’s disease can cause cardiomyopathy (weakness of the heart) as well as infertility and repeated miscarriage as a result of thyroid impairment.

Diagnosis

Because of the diverse range of potential symptoms, Wilson’s disease can often be difficult to diagnose. Particularly if the symptoms are vague, the disease can easily be mistaken for everything from heavy metal poisoning and hepatitis C to medication-induced lupus and cerebral palsy.

If Wilson’s disease is suspected, the investigation will include a review of the physical symptoms along with a number of diagnostic tests, including:

  • Liver enzyme tests
  • Blood tests to check for high levels of copper and low levels of ceruloplasmin (the protein which transports copper through blood)
  • Blood glucose tests to check for low blood sugar levels
  • 24-hour urine collection to test for acidity and calcium levels
  • Liver biopsy to measure the severity of copper accumulation
  • Genetic tests to confirm the presence of the ATB7B mutation

Treatment

Early diagnosis of Wilson’s disease generally confers to better outcomes. Persons diagnosed with the disease are typically treated in three steps:

  1. Treatment usually begins with the use copper-chelating drugs to remove excess copper from the system. Penicillamine is usually the first-line drug of choice. It works by binding with copper, allowing the metal to be more readily excreted in urine. Side effects are sometimes significant and may include muscle weakness, rash, and joint pain. Among those experiencing symptoms, 50 percent will experience a paradoxical worsening of symptoms. In such case, second-line drugs may be prescribed.
  2. Once copper levels are normalized, zinc may be prescribed as a form of maintenance therapy. Zinc taken orally prevents the body from absorbing copper. Stomach ache is the most common side effect.
  3. Dietary changes ensure that you avoid consuming unneeded copper. These include such copper-rich foods as shellfish, liver, nuts, mushrooms, dried fruits, peanut butter, and dark chocolate. Copper-containing supplements, such as multivitamins and those used to treat osteoporosis, may also require substitution.

Persons with serious liver disease who fail to respond to treatment may require a liver transplant.

Sources:

Borges Pinto, R.; Reis Schneider, A.; and da Silveira, T. "Cirrhosis in children and adolescents: An overview." World Journal of Hepatology. 2015; 7():392-405.

Patil, M.; Sheth, K.; Krishnamurthy, A. et al. "A Review and Current Perspective on Wilson Disease." Journal of Clinical and Experimental Hepatology. 2013; 3(4):321-336.

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