On the other hand, in patients with T1DM and CP carrying A allele of the IL-17A −197 polymorphism, T.d. in subgingival biofilm occurred less frequently than in subjects without this allele (26.9% versus 50.0%, P < 0.05, OR = 0.37, 95% CI = 0.13–1.01, Table 5). The gene discussed is IL17A; the disease is type 1 diabetes mellitus.