Evaluation of genome-wide association signals for nonsyndromic cleft lip with or without cleft palate in a multiethnic Brazilian population.

Objective: To evaluate previous nonsyndromic cleft lip with or without cleft palate (NSCL±P) associated signals in 4p16.2, 8p11.23, 12q13.13, 12q13.2 and 17q21.32 in a multiethnic Brazilian cohort.

Design: The single nucleotide polymorphisms (SNPs) rs34246903 in 4p16.2, rs13317 in 8p11.23 (FGFR1, fibroblast growth factor receptor 1), rs3741442 in 12q13.13, rs705704 in 12q13.2 and rs4968247 in 17q21.32 were genotyped with TaqMan allelic discrimination assays in a case-control sample including 801 NSCL±P patients [233 nonsyndromic cleft lip (NSCLO) and 568 nonsyndromic cleft lip and palate (NSCLP)] and 881 healthy controls. Multiple logistic regression analyses, considering sex and genomic ancestry as covariates, were conducted, and the p value was adjusted with Bonferroni multiple correction testing (p ≤ 0.01).

Results: Although several associations were identified, those that resisted the multiple correction testing involved the alleles and genotypes of rs34246903 and rs13317. The NSCLO group had a lower frequency of the minor C allele of rs34246903 compared to controls, giving an odds ratio (OR) of 0.74 [95% confidence interval (CI): 0.59-0.93, p = 0.01]. The rs34246903 CC genotype (homozygous) and the recessive model revealed significant protective associations with NSCLO, yielding ORs of 0.50 (95% CI: 0.29-0.85, p = 0.005) and 0.55 (95% CI: 0.33-0.93, p = 0.01) respectively. The presence of C variant allele of rs13317 (OR: 0.81, 95% CI: 0.69-0.96, p = 0.01) as well the TC genotype (OR: 0.77, 95% CI: 0.62-0.94, p = 0.01) and the dominant model (OR: 0.77, 95% CI: 0.63-0.94, p = 0.009) showed significant associations with reduced risk of NSCL±P.

Conclusion: Our study is the first to support the association of rs34246903 (4p16.2) with NSCLO and rs13317 within FGFR1 with NSCL±P in the highly admixed Brazilian population. Further studies are needed to determine the functionality of those SNPs or to identify the causal markers in linkage disequilibrium with those susceptibility markers.