All of the following are true about Wilson disease, except
**Core Concept**
Wilson disease is a rare genetic disorder characterized by excessive accumulation of copper in the body, particularly in the liver, brain, and other vital organs. This accumulation leads to the formation of toxic compounds that cause cellular damage and dysfunction. The disease is inherited in an autosomal recessive pattern, meaning that an individual must inherit two defective genes (one from each parent) to express the condition.
**Why the Correct Answer is Right**
Wilson disease is caused by mutations in the ATP7B gene, which encodes a copper-transporting P-type ATPase involved in the regulation of copper levels in the liver. The disease leads to the accumulation of copper in the liver, causing liver damage, hepatitis, and cirrhosis. In the brain, copper accumulation leads to the formation of toxic compounds that cause neurodegeneration and symptoms such as tremors, rigidity, and difficulty with coordination and balance. The excessive copper accumulation can also lead to Kayser-Fleischer rings, a hallmark sign of Wilson disease.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Wilson disease is not caused by a deficiency of ceruloplasmin, a protein that binds and transports copper in the blood. Instead, the disease is caused by mutations in the ATP7B gene.
**Option B:** This option is incorrect because Wilson disease is not associated with an increase in serum ceruloplasmin levels. In fact, the levels of ceruloplasmin are often decreased in Wilson disease due to the impaired copper transport.
**Option C:** This option is incorrect because Wilson disease is not associated with an increase in urinary copper excretion. In fact, the levels of urinary copper are often decreased in Wilson disease due to the impaired copper transport.
**Clinical Pearl / High-Yield Fact**
Wilson disease is a classic example of a disorder that is caused by a defect in a specific gene involved in the regulation of a vital cellular process. This highlights the importance of understanding the genetic basis of diseases and the role of specific genes in maintaining normal cellular function.
**Correct Answer: A.**