ITGB2 and periodontitis: For example, patients with leukocyte adhesion deficiency‐I with a genetic defect of cluster of differentiation 18 (CD18) or integrin beta chain‐2 usually develop generalized periodontitis, clinically mimicking aggressive periodontitis at a young age.52, 53 However, the microbial composition of subgingival plaque in patients with leukocyte adhesion deficiency‐I is different from that in patients with either chronic or aggressive periodontitis.