Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The aim of this study was to evaluate the influence of the gamma-aminobutyric acid receptor type A beta-3 subunit (GABRB3) polymorphisms in patients with nonsyndromic cleft lip and/or palate (NSCL/P). We carried out a structured case-control analysis of three GABRB3 polymorphisms (rs4477673, rs6576618, and rs981778) in 229 patients with nonsyndromic cleft lip with or without cleft palate (CL +/- P) and in 314 unaffected controls from Brazil. The polymorphisms were genotyped by the TaqMan 5'-exonuclease allelic discrimination assay, and each sample was independently typed for 40 biallelic short insertion/deletion markers (INDELs) to characterize the genomic ancestry. The genotype distributions of the three polymorphisms were as expected by the Hardy-Weinberg equilibrium test. After adjustment to ancestry contribution, the minor A allele of rs981778 was associated with NSCL/P, but significant results did not persist after Bonferroni correction for multiple tests. Similarly, the haplotype analysis revealed that the CCA haplotype (C allele of rs4477673, C allele of rs6576618, and A allele of rs981778) was correlated with NSCL/P, but this association did not remain statistically significant after Bonferroni correction. With a weak association, our data do not support the hypothesis that the GABRB3 variants are a cause of NSCL/P, but further studies are warranted.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.323125129Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)