Structure of the periodontium in cathepsin C-deficient mice

Papillon–Lefevre syndrome is characterized by increased susceptibility to early‐onset periodontitis and is caused by mutations in the cathepsin C gene. How deficiency of the enzyme relates to an increased periodontal infection risk is still not entirely clear. One possibility is that the deficiency leads to changes in the structure of the periodontal tissues as a result of which its barrier function to pathogens is compromised. We studied the structure of the periodontium in 9‐month‐old cathepsin C‐deficient mice (cathepsin C–/–) and compared this with age‐matched wild‐type mice. Our observations showed that the overall structure of the gingiva, periodontal ligament, alveolar process, and cementum layer are normal in cathepsin C–/– mice, with one exception, namely that epithelial rests of Malassez in the periodontal ligament of the cathepsin C–/– mice are slightly enlarged. In both experimental and control animals, we noted cyst formation in rests of Malassez. No signs of periodontal infection were observed. It is concluded that cathepsin C deficiency does not lead to major changes in the structure of the periodontium.