An unusual case of Papillon-Lefevre syndrome is reported. The 10-year-old boy exhibited all symptoms typical of this disease except premature loss of primary teeth. The patient's past history, his status at first examination, an initial successful treatment phase, the efforts made at long-term maintenance and the eventual treatment failure are described. The bacterial plaque covering subgingival root surfaces was examined by scanning electron microscopy, and the histopathologic alterations of glossy, glaring red gingival tissue halos are described and discussed with respect to the pathogenesis of periodontitis associated with this syndrome.