The aim of this study was to explore whether schizophrenia occurrence is associated with polymorphisms in the 5' regulatory region of GABRB3 (gamma-aminobutyric acid type A receptor beta 3, subunit gene). The study included 324 patients with schizophrenia and 327 unaffected participants; all individuals were northern Han Chinese. Genotype and haplotype frequency distributions were compared for the 2 groups by means of PCR amplification and direct sequencing of the promoter region of GABRB3. The genotype distribution among control participants was in accordance with the Hardy-Weinberg equilibrium. Five common single-nucleotide polymorphism (SNP) sites were detected in the 5' promoter region of GABRB3: rs4243768, rs7171660, rs4363842, rs4906902, and rs8179184. Only rs8179184 and rs4906902 differed significantly in frequency between controls and cases (P < 0.05); this difference remained significant when only women in each group were compared. The 2 SNP sites showed linkage disequilibrium, resulting in 2 haplotypes: T-G and C-A. The frequency of C-A was significantly higher among patients with schizophrenia than among controls. Our findings suggest that rs4906902 and rs8179184 in the 5' promoter region of GABRB3 are associated with schizophrenia. The C-A haplotype may entail an increased risk of schizophrenia, and the onset of schizophrenia may be gender-specific.
Keywords: GABRB3; Schizophrenia; Single-nucleotide polymorphisms (SNPs); γ-Aminobutyric acid.