Association of Interleukin-1 Receptor Antagonist Gene Polymorphisms With Generalized Aggressive Periodontitis in an Iranian Population

Background: Periodontitis is a multifactorial disease that occurs in the presence of bacteria, environmental factors, and genetic predispositions. It is suggested that polymorphisms in the interleukin-1 (Ill) receptor antagonist gene have an important role in the susceptibility of the host to periodontitis. This study investigates the association of a variable number of tandem repeat polymorphism in the IL1RN gene with generalized aggressive periodontitis (GAgP). Methods: Sixty-six subjects with GAgP and 56 periodontally healthy subjects took part in the study. All subjects were of Iranian Khorasanian (north-east province of Iran) descent. Subjects were identified through clinical examinations and radiographs at the Mashad Dental School and Dental Research Center. DNA was extracted from peripheral blood cells, and different genotypes were detected using polymerase chain reaction amplification and fragment-size analysis. Data were analyzed using the chi(2) test. Results: The frequencies of the IL1RN genotype A1A2 (chi(2) test; P = 0.001) and allele A2 (chi(2) test; P = 0.006) were found to be significantly increased in patients with GAgP compared to normal subjects. Conclusion: These findings suggest that the polymorphic IL1RN gene is a risk determinant for generalized aggressive periodontitis in the Iranian Khorasanian population. J Periodontol 2010;81:1342-1346.