**Core Concept**
Wilson's disease is a genetic disorder characterized by excessive accumulation of copper in the body, particularly in the liver, brain, and other organs. This leads to a range of symptoms, including neurological and psychiatric manifestations, due to copper toxicity. The presence of Kayser-Fleischer rings, which are golden brown discolorations in the Descemet membrane of the cornea, is a hallmark of Wilson's disease.

**Why the Correct Answer is Right**
The accumulation of copper in the body is due to a defect in the ATP7B gene, which is responsible for regulating copper transport and metabolism. In Wilson's disease, the mutated gene leads to impaired copper excretion, resulting in its accumulation in various organs. The copper deposits in the Descemet membrane of the cornea cause the characteristic golden brown discoloration known as Kayser-Fleischer rings. This is a key diagnostic feature of Wilson's disease, particularly in children and adolescents.

**Why Each Wrong Option is Incorrect**
**Option A:** Fabry's disease is a genetic disorder that affects the metabolism of lipids, leading to the accumulation of globotriaosylsphingosine in various organs. While it can cause a range of symptoms, including neurological and psychiatric manifestations, it is not typically associated with Kayser-Fleischer rings.

**Option C:** Glycogen storage disease is a group of disorders that affect the metabolism of glycogen, leading to its accumulation in various organs. While some forms of glycogen storage disease can cause neurological symptoms, they are not typically associated with Kayser-Fleischer rings.

**Option D:** Acute rheumatic fever is an autoimmune disease that can cause a range of symptoms, including arthritis, carditis, and neurological manifestations. However, it is not associated with Kayser-Fleischer rings or the accumulation of copper in the body.

**Clinical Pearl / High-Yield Fact**
Kayser-Fleischer rings are not only a diagnostic feature of Wilson's disease but also a sign of other conditions, such as primary biliary cirrhosis and Menkes disease. Remember that Kayser-Fleischer rings are a key indicator of copper accumulation in the body and should prompt further investigation for underlying metabolic disorders.

**Correct Answer:**
✓ Correct Answer: B. Wilson's disease