**Question:** Which of the following is true of Wilson's disease:

A. Wilson's disease is caused by mutations in the ATP7B gene.
B. Wilson's disease is characterized by abnormal liver function tests.
C. Wilson's disease is a rare condition affecting only a few thousand people worldwide.
D. Wilson's disease is a pediatric-onset disease presenting in children under 10 years old.

**Correct Answer:**

**Wilson's disease is caused by mutations in the ATP7B gene.**

**Core Concept:** Wilson's disease is a rare genetic disorder characterized by the accumulation of copper in the liver, brain, and other organs due to mutations in the ATP7B gene. The ATP7B gene encodes for a protein called copper-transporting ATPase, which is involved in the excretion of copper from the body. Mutations in this gene impair copper excretion, leading to copper overload and subsequent organ damage.

**Why the Correct Answer is Right:**

The ATP7B gene is crucial for maintaining copper homeostasis in the body. When mutations occur in this gene, the copper-transporting ATPase protein is impaired, resulting in the accumulation of copper within hepatocytes (liver cells). This copper overload leads to liver cirrhosis and neurological symptoms. Wilson's disease is an autosomal recessive disorder, which means an individual must inherit two mutated copies of the ATP7B gene to develop the disease.

**Why Each Wrong Option is Incorrect:**

**Option A:** Wilson's disease is primarily characterized by its neurological symptoms like tremors, dystonia, and psychiatric disturbances. While liver involvement is a key feature, the statement "Wilson's disease is a pediatric-onset disease presenting in children under 10 years old" is incorrect. Wilson's disease can present at any age, including childhood, but the mean age of onset is typically in the late teenage years or early adulthood.

**Option B:** Wilson's disease is not primarily characterized by abnormal liver function tests. While liver involvement is a prominent feature, the disease's presentation as an abnormal liver function test is not its defining feature. Wilson's disease affects multiple organs, including the liver, brain, and eyes.

**Option C:** The statement "Wilson's disease is a rare condition affecting only a few thousand people worldwide" is an oversimplification. Wilson's disease is relatively common, affecting approximately 1 in 30,000 individuals globally.

**Option D:** Wilson's disease presents with a wide range of clinical manifestations, including liver symptoms, neurological symptoms, and psychiatric symptoms. The statement "Wilson's disease is primarily an eye disease" is incorrect. While the eyes might be affected, Wilson's disease primarily affects the liver, brain, and other organs due to copper accumulation.

**Clinical Pearl:** Wilson's disease is a crucial condition to know for medical students and residents, as its diagnosis is essential for appropriate treatment and management. Early diagnosis can prevent severe neurological complications and liver failure. Treatment includes copper-chelating agents like penicillamine and trientine to reduce copper accumulation, along with