Significant Evidence of Association Between Polymorphisms in ZNF533, Environmental Factors, and Nonsyndromic Orofacial Clefts in the Western Han Chinese Population

The etiology of nonsyndromic orofacial clefts (NSOC) has been considered "complex'' or "multifactorial.'' Etiologic heterogeneity induces disparities in the results among different populations. The zinc finger protein 533 (ZNF533) and several environmental factors have been revealed to be associated with NSOC in several populations. We investigated three single-nucleotide polymorphisms (SNPs) and 10 environmental factors in 211 case-parent trios and 188 control individuals in the Western Han Chinese population to confirm the relationship between ZNF533, environmental factors, and the etiology of NSOC in the Western Han Chinese population. The transmission disequilibrium test, case-control analysis, multiple logistic regression, log-linear model, and conditional logistic regression were tested to confirm the contribution of the ZNF533 gene and environmental factors to the etiology of NSOC. Strong statistically significant evidence of association was found between the rs6757845 and rs1139 markers and NSOC. The haplotype G-G for rs6757845-rs1139 showed significant overtransmission among cleft lip with or without cleft palate (CL/P) trios and among cleft palate only trios. Additional 11 and 5 haplotypes were significantly overtransmitted and undertransmitted among CL/P and among cleft palate only trios, respectively. Maternal disease, use of medication, and passive smoking during the first trimester of pregnancy may increase the risk of NSOC. Maternal folic acid supplementation during the first trimester of pregnancy showed a protective effect on the etiology of NSOC. Genotype-environment interaction test showed a significant evidence of interaction effects between the genotypes at rs6757845 and maternal passive smoking during the first trimester among CL/P trios. These results confirm the effects of the ZNF533 gene and environmental factors on the etiology of NSOC.