Background: The extent of the contribution of rs642961 polymorphism of interferon regulatory factor-6 (IRF6) gene with susceptibility to the syndromic cleft lip with or without cleft palate (NSCL/P) in the Iranian patients is still unknown. Thus, to test the role of IRF6 in NSCL/P susceptibility in an Iranian population, we performed a population based case-control stud. Methods: One-hundred ten patients with NSCL/P and 110 matched healthy subjects were recruited to this population-based study. The IRF6 rs642961 polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Results: Participants did not differ significantly by age and gender (P > 0.05). The AA, AG, and GG genotypes frequencies of the IRF6 rs642961 polymorphism in the NSCL/P cases were 27.3%, 53.6% and 19.1%, respectively while the corresponding frequencies in the healthy subjects were 34.5, 56.4% and 9.1%, respectively. There was a significant association between homozygote mutant genotype (GG) of IRF6 rs642961 polymorphism and increased risk of NSCL/P (OR = 2.360, 95% CI 1.055-5.280, P = 0.037). Conclusion: the current study suggested that IRF6 rs642961 polymorphism might be associated with susceptibility to NSCL/P in an Iranian population. However, well-designed epidemiological studies with larger sample size are needed to further validate our results. Keywords: Nonsyndromic, Cleft lip, Cleft palate, Interferon regulatory factor 6, Polymorphism
