A 3-year-old child has severe symmetrical palmoplantar keratoderma and premature loss of both primary and secondary dentition due to destructive periodontitis starting soon after teeth erupt. Sweating, hair and nails are normal. The defective enzyme in this condition is:

• A Connexin 26
• B Cathepsin C ✓
• C Loricrin
• D Transglutaminase 5

Explanation

Papillon-Lefevre syndrome is autosomal recessive, caused by loss-of-function mutations in CTSC encoding cathepsin C, a lysosomal protease expressed in epithelium and immune cells. The triad is palmoplantar keratoderma with erythematous borders plus severe periodontitis causing tooth loss by adolescence. Connexin 26 defects cause Vohwinkel keratoderma with starfish-like keratoses and deafness, and transglutaminase 5 causes peeling skin disease, neither of which destroys the periodontium.

Reference: Fitzpatrick's Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.