Association between brain-derived neurotropic factor gene variant (rs6265; C > T) and schizophrenia, its psychopathology and intelligence

Abstract Background and objectives The etiology of schizophrenia (SCZ) is not yet known, but the genetic factor has an essential role. Its heritability is estimated up to 85 percent. This study aimed to determine whether the selected brain-derived neurotropic factor (BDNF) gene variant (rs6265) is associated with SCZ, its psychopathology and intelligence quotient (IQ). Methods Rs6265 was genotyped in 159 participants, including 71 unrelated patients with SCZ (males = 40 [56%]) and 88 healthy controls (males = 35 [40%]). Psychopathology assessment was done by using positive and negative symptoms scale (PANSS), and IQ was measured by Wechsler adult intelligence scale (WAIS). COCAPHASE and CLUMP22 softwares were used to compare allele and genotype frequencies respectively. Two-way multivariate ANOVA was done using SPSS22 to evaluate the effects of the group (patients and healthy control) and the genotype on the test scores, including PANSS and WAIS scores, considering sex and smoking status as covariates. Results The study showed that the BDNF rs6265 C allele and CC genotypes, psychopathology, including PANSS scores, and also IQ were significantly different in all, male and female patients compared to healthy participants. For rs6265, we found significantly higher frequencies of the C allele (P = 0.04) in all participants with SCZ. The findings also revealed that BDNF polymorphism (rs6265) increased significantly the risk of SCZ in different genetic models. Conclusion The results showed that the BDNF rs6265 may be associated with the risk of SCZ development in an Iranian group of patients with SCZ. These results may be helpful in better understanding the role of the BDNF gene in the pathogenesis of the disorder.