**Question:** True about Wilson's disease -

A. Wilson's disease is a genetic disorder causing copper accumulation in the liver and brain, leading to neurological symptoms and liver dysfunction.
B. Wilson's disease is caused by mutations in the ATP7B gene, which leads to an impaired ability to excrete copper.
C. Wilson's disease is characterized by the presence of Kayser-Fleischer rings in the eyes, due to copper buildup in the cornea.
D. Wilson's disease is a rare disorder, with an estimated prevalence of 1 in 30,000.

**Correct Answer:** D. Wilson's disease is a rare disorder, with an estimated prevalence of 1 in 30,000.

**Core Concept:** Wilson's disease is a rare genetic disorder characterized by copper accumulation in the liver and brain. It is caused by mutations in the ATP7B gene, which impairs the excretion of copper from the body. This leads to neurological symptoms and liver dysfunction.

**Why the Correct Answer is Right:** The correct answer (D) refers to the rarity of Wilson's disease, which is justified by its low prevalence of 1 in 30,000. This statistic highlights the importance of being aware of the condition, despite its low incidence.

**Why Each Wrong Option is Incorrect:**

A. Wilson's disease is indeed a genetic disorder with copper accumulation in the liver and brain, but the detailed explanation about the genetic cause and copper accumulation is not relevant to the prevalence question.

B. The ATP7B gene mutation is a key factor in Wilson's disease, but the focus should be on the prevalence rather than the genetic cause.

C. Kayser-Fleischer rings in the eyes are indeed a characteristic finding in Wilson's disease, but the prevalence statistic is more important to emphasize.

**Clinical Pearl:** Wilson's disease highlights the importance of considering rare diseases in clinical practice, despite their low prevalence. Awareness and early diagnosis are crucial for effective management and patient outcomes.