A 40 yr old woman presents with progressive palmoplantar pigmentation. X-ray spine shows calcification of interveebral discs. On adding Benedict’s reagent to urine, it gives greenish brown precipitate and blue-black supernatant fluid. What is the diagnosis?

**Core Concept**
The patient's presentation suggests a disorder of copper metabolism, specifically a condition characterized by excessive accumulation of copper in tissues, leading to its deposition in various organs, including the liver, brain, and joints.

**Why the Correct Answer is Right**
The greenish-brown precipitate and blue-black supernatant fluid on adding Benedict's reagent to urine indicate the presence of copper in the urine. The patient's symptoms, including progressive palmoplantar pigmentation and calcification of intervertebral discs, are classic features of Wilson's disease, an autosomal recessive disorder caused by mutations in the ATP7B gene, which encodes a copper-transporting ATPase. This enzyme plays a crucial role in regulating copper metabolism by facilitating its excretion into bile. In Wilson's disease, the impaired function of ATP7B leads to copper accumulation in tissues, resulting in oxidative stress, inflammation, and tissue damage.

**Why Each Wrong Option is Incorrect**
**Option A:** This is not a known condition associated with the described symptoms and laboratory findings.
**Option B:** While acromegaly can cause skin pigmentation, it is not typically associated with calcification of intervertebral discs or the characteristic urine test results.
**Option C:** This is a distractor and does not match the clinical presentation.

**Clinical Pearl / High-Yield Fact**
Wilson's disease often presents with neurological symptoms, including tremors, ataxia, and dystonia, due to copper deposition in the brain.

**Correct Answer: D. Wilson's disease**

✓ Correct Answer: B. Alkaptonuria