Piebaldism refers to –
**Core Concept**
Piebaldism is a rare **genetic disorder** characterized by the absence of **melanocytes** in affected areas of the skin and hair, resulting in patches of **depigmentation**. This condition is often associated with **white forelock** and **vitiligo-like** skin lesions. The underlying cause involves mutations in the **KIT** gene.
**Why the Correct Answer is Right**
The correct answer is related to the definition of piebaldism, which is a condition affecting **melanocyte development**. The **KIT** gene plays a crucial role in the migration and survival of melanocyte precursors during embryogenesis. Mutations in this gene lead to the characteristic **depigmented patches** seen in piebaldism.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the primary feature of piebaldism.
**Option B:** This option is also incorrect as it does not relate to the genetic basis of the disorder.
**Option C:** Similarly, this option is wrong because it does not involve the **KIT** gene or **melanocyte** development.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that piebaldism is often associated with a **white forelock**, which is a distinctive patch of white hair on the forehead. This feature, combined with **vitiligo-like** skin lesions, should raise suspicion for piebaldism.
**Correct Answer:** D. Congenital depigmented patches.