Objective: To investigate whether an association occurred between the IRF6 G820A polymorphism and nonsyndromic cleft lip with or without cleft palate (CL+/-P) or cleft palate only (CPO) in Chinese patients.
Design and setting: Case-controlled study at the West China Hospital of Stomatology, Sichuan University, China.
Subjects: A total of 91 patients with cleft lip and/or palate (CL/P) and 96 unrelated, healthy individuals with no family history of CL/P were genotyped.
Methods: The IRF6 G820A polymorphism was genotyped by restriction digestion of polymerase chain reaction products with BseLI. Chi-square statistics were used to make case-controlled comparisons.
Results: The frequency of the A allele was significantly increased and the frequency of the G allele was reduced in CPO patients in comparison with control subjects. The 820GG genotype had a significantly lower frequency in patients with CPO than in controls, with an odds ratio of 0.25 (95% confidence interval, -0.061 to 0.57). No difference in the distribution of genotypes was noted between CL+/-P patients and the total group of CL/P patients compared with controls.
Conclusions: The present findings indicate that the 820A allele is more frequent in the Chinese CPO population and may confer an increased risk for CPO in these individuals. The G820A variant may be in linkage disequilibrium with other disorder-causing mutations. CL+/-P or CPO results should be analyzed separately and stratified in future studies.