Papillon-Lefèvre syndrome (PLS) is a rare autosomal recessive genetic disorder caused by cathepsin C deficiency. The syndrome is characterized by palmoplantar keratoderma and destructive periodontal disease, which manifests as gingival inflammation and loss of most primary and permanent teeth.

Cathepsin C is necessary for granzyme B and natural killer cell function, and its deficiency is associated with reduced immunologic response to bacteria. The presence of virulent pathogens, specifically Actinobacillus actinomycetemcomitans, within the mouth has been proposed to contribute to the progression of PLS.

The clinical age of onset is between ages 2 and 3. Consanguinity is a high risk factor for PLS. There is no racial predominance, and men and women are equally affected.

Symptoms and Signs
Skin
Hyperkeratosis of the palmar and plantar surfaces appears in the first few years of life. The red, scaly, and well-demarcated plaques extend to the margins of the palms and span over the thenar eminence. Lesions on the plantar surface spread to the edges of the sole, reaching to the Achilles tendon (transgrediens). Knees and elbows may manifest hyperkeratotic plaques in some patients. Nail dystrophy has also been reported.

Mouth
Gingival inflammation typically coincides with the presentation of palmoplantar hyperkeratosis.

Deciduous teeth are often lost by age 5, after which there is a decrease in gingival inflammation. As permanent teeth begin to appear, the inflammatory process restarts and symptoms recur. By age 16, all permanent teeth, except for the third molars typically, are lost.