**Core Concept**
Papillon-Lefèvre syndrome is a rare autosomal recessive genetic disorder characterized by early-onset severe destructive periodontitis and palmoplantar keratosis. It is caused by mutations in the *NEMO* gene (NFKB1), leading to dysregulation of the NF-κB signaling pathway, which plays a key role in immune and inflammatory responses.

**Why the Correct Answer is Right**
- **Destructive periodontitis** occurs in childhood, with rapid bone loss and tooth loss, due to uncontrolled inflammation from defective immune regulation.
- **Palmar-plantar keratosis** manifests as thick, hyperkeratotic skin lesions on palms and soles, a hallmark clinical feature.
- **Calcification of dura** is a rare but documented finding in some cases, reflecting systemic involvement of connective tissues.
Thus, all listed features are clinically recognized in Papillon-Lefèvre syndrome.

**Why Each Wrong Option is Incorrect**
Option A: Incorrect — While destructive periodontitis is a key feature, it is not the only one; the option is misleadingly presented as a standalone feature.
Option B: Incorrect — Palmar-plantar keratosis is a feature, but it is not the only one, and presenting it alone misses the broader clinical picture.
Option C: Incorrect — Dural calcification is rare and not a primary feature, though it can occur; it is not a defining or commonly cited feature.

**Clinical Pearl / High-Yield Fact**
Papillon-Lefèvre syndrome is a rare condition with early tooth loss and skin lesions — remember the classic triad: **early-onset periodontitis, palmoplantar keratosis, and systemic inflammation**. Genetic testing for *NFKB1* mutations is essential for diagnosis.

✓ Correct Answer: D. all the above