PRTN3 and periodontitis: Therefore, in the present study it was hypothesized that hCAP-18/LL-37 deficiency might be caused by the lack of proteinase 3 and cathepsin C enzymes in GCF of patients with generalized aggressive periodontitis, and the deficiency of these enzymes might contribute to multifactorial etiology of generalized aggressive periodontitis, by modifying host responses.