Association between IRF6 rs642961 polymorphism and non-syndromic cleft lip with or without a cleft palate: a systematic review and meta-analysis

Non-syndromic cleft lip with or without a cleft palate (NSCL/P) is one of the most common newborn malformations. sPrevious studies have reported that genetic variations of interferon regulatory factor 6 (IRF6) polymorphisms are associated with NSCL/P. However, the effect sizes of individual studies still vary. Our present study is a meta-analysis to investigate the association of IRF6 rs642961 polymorphism with NSCL/P. A literature search in PubMed was performed to select eligible literatures including observational studies which evaluated association between IRF6 polymorphisms and NSCL/P. We conducted a systematic review and a meta-analysis on all qualified eight case-control studies that included 1,899 cases and 3,458 controls to investigate the association between NSCL/P and IRF6 rs642961 polymorphism. We found that the A allele had a higher risk of NSCL/P (odds ratio (OR)=1.64, 95% confidence interval (CI)=1.37-1.97) in comparison to the G allele of IRF6 rs642961 polymorphism. The rs642961 A allele in the Asian population had an increased risk of NSCL/P (OR=2.12, 95% CI=1.66-2.71). Under various genetic models, the A allele of IRF6 rs642961 polymorphism in Asian population showed a significantly increased risk of NSCL/P under the dominant model (OR=2.19, 95% CI=1.64-2.91), recessive model (OR=4.49, 95% CI=2.26-8.92), homozygous model (OR=5.86, 95% CI=2.90-11.8), and heterozygous model (OR=1.91, 95% CI=1.42-2.57). Our major findings suggest that association of IRF6 rs642961 polymorphism and NSCL/P is predominant in an Asian population rather than non-Asian populations, which might be useful in clinical diagnoses and treatment of patients with NSCL/P