Since the Leu125Val (C + 373G) polymorphism is in the first and second domain of PECAM-1 and the importance of this domain and also previous findings showing the association of this polymorphism with diseases such as coronary artery disease, atherosclerosis, and ischemic heart diseases; [9, 14] we decided to investigate its possible association with periodontitis. Here, PECAM1 is linked to periodontitis.