Patients and healthy donors Five patients with established diagnose of PLS are under periodontal treatment at the Department of Periodontology, Center for Dental, Oral, and Maxillofacial Medicine (Carolinum) of the Johann Wolfgang Goethe-University Frankfurt am Main. Antiinfective therapy with adjunctive antibiotics has been rendered to all of them and they are under regular and frequent supportive therapy. The Department of Periodontology has contact to additional 5 PLS patients that are edentulous or under periodontal therapy elsewhere. All patients underwent complete oral examinations as well as inspection of the skin of the palms and soles. Each adult patient or parents received clinical and genetic counselling, and signed a consent form, approved by the ethic committees of the Universities of Dresden and Frankfurt/Main. Clinical data and mutations of all patients have been reported before. All these patients were invited to take part in this study. Healthy donors had abstained from taking drugs for two weeks prior to the study. Due to wide spread use of oral contraceptives only male probands were chosen. The study complied with the rules of the Declaration of Helsinki and was approved by the Institutional Review Board for Human Studies of the Medical Faculty of the Johann Wolfgang Goethe-University Frankfurt/Main (Application# 31/05). All participating individuals were informed on risks and benefit as well as the procedures of the study and gave written informed consent.