Association of WNT9B Gene Polymorphisms With Nonsyndromic Cleft Lip With or Without Cleft Palate in Brazilian Nuclear Families

Objective: Nonsyndromic cleft lip with or without cleft palate (NSCL +/- P) is a common craniofacial anomaly of complex etiology in people. WNT pathway genes have important roles during craniofacial development, and an association of WNT genes with NSCL +/- P has been demonstrated in different populations. The aim of this study was to evaluate the association between polymorphisms in WNT3 and WNT9B genes and CL/P in Brazilian families. Patients: Seventy nuclear families composed of an affected child and the child's unaffected parents were examined clinically. Saliva samples were collected for molecular analyses. Design: Three single nucleotide polymorphisms (SNPs) in the WNT3 gene and two in WNT9B were investigated in real-time polymerase chain reaction using TaqMan chemistry. The Family-Based Association Test and the transmission disequilibrium test were used to verify the association between each marker allele and NSCL +/- P. The level of significance was established at P <= .01 after Bonferroni correction. Results: A positive association was detected between NSCL +/- P and SNP rs1530364 in the WNT9B gene. Haplotype analysis showed an association of WNT3 and WNT9B haplotypes. No association was detected between NSCL +/- P and individual SNPs in WNT3. Conclusion: Our study further supports the involvement of WNT9B as a cleft susceptibility gene in Brazilian families experiencing NSCL +/- P. Although additional studies are still necessary to unveil the exact mechanism by which WNT genes would contribute to NSCL +/- P, allelic polymorphisms in these genes and their interactions may partly explain the variance of individual susceptibility to NSCL +/- P.