OBJECTIVETo assess the association between polymorphism of interferon regulatory factor 6 (IRF6) gene rs2235371 locus and nonsyndromic cleft lip with or without cleft palate in Chinese population.

METHODSBlood samples from 106 patients and their parents and 129 controls and their parents were collected. The polymorphism of IRF6 rs2235371 locus was determined with PCR-restriction fragment length polymorphism (PCR-RFLP) method. Case-control analysis, transmission disequilibrium test(TDT), haplotype-based haplotype relative risk analysis (HHRR) and family-based association test (FBAT) were carried out.

RESULTSBy case-control analysis, no significant difference was found in the frequencies of GG, GA and AA genotypes of rs2235371 locus between the patient group and control group (P> 0.05), but there was a significant difference in allelic frequencies (P< 0.05). There was also a significant difference in genotype and gene frequencies of rs2235371 variant between family members from cleft lip only group and control group. However, in cleft lip with cleft palate group, no such difference was observed. TDT analysis suggested a linkage in the presence of disequilibrium (chi-square=5.56, P=0.024). Results of HHRR analysis (chi-square=5.115, P=0.024) and FBAT (Z=2.218, P=0.027) also indicated an association between IRF6 rs2235371 variant and the risk of NSCL with or without cleft palate.

CONCLUSIONGenetic polymorphism of IRF6 gene rs2235371 locus is associated with NSCL with or without cleft palate.