Haim-Munk syndrome presents with severe and extensive skin manifestations. In addition to the marked palmoplantar keratosis, patients have scaly erythematous and circumscribed patches on the elbows, knees, forearms, shins and dorsum of the hands. Severe, early-onset progressive periodontitis that affects both the deciduous and permanent dentitions and presents with gingival inflammation and alveolar bone destruction is a hallmark of the disease. Onychogryposis, arachnodactyly, acroosteolysis and pes planus are additional features that help to distinguish HMS from other forms of palmoplantar hyperkeratosis. A peculiar deformity of the fingers (tapered, pointed phalangeal ends and a claw-like volar curve) is typical. Destructive arthritis of the wrist and shoulder joints has been reported in isolated cases. Patients with HMS have increased susceptibility to infections.
The syndrome is caused by germline mutations in the lysosomal protease cathepsin C (CTSC) gene mapped to chromosome 11q14.1-q14.3. Mutations in the same gene cause the clinically related disorders Papillon-Lefèvre syndrome (PLS) and prepubertal periodontitis.
