Association of the brain-derived neurotrophic factor gene G196A rs6265 polymorphisms and the cognitive function and clinical symptoms of schizophrenia

This study aimed to explore the association between BDNF G196A gene rs6265 polymorphisms and the cognitive function and clinical symptoms of schizophrenia. Methods: BDNF G196A rs6265 genotype and allele frequency were measured using Polymerase Chain Reaction (PCR) methods in 224 drug-free patients with schizophrenia and 220 controls. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS), and cognitive functioning was assessed using the Wisconsin Card Sorting Test (WCST) and the Trail Making Test (TMT). In the patient group, differences in severity of symptoms across the three genotypes (i.e., G/G, G/A and A/A) of G196A were assessed using one-way analysis of variance. Results G/A genotype had higher frequencies than GG or AA genotype in both patients and controls. There was no significant difference in G/G, G/A, A/A genotype frequency between patients and controls (P > 0.05). The allele G had higher frequencies than allele A in both patients and controls. There was no significant difference in G or A allele frequency between patients and controls (P > 0.05). There was significant difference in A/A genotype frequency between positive group patients and negative group patients. There was no significant difference in cognitive performance between patients with G/G, G/A and A/A genotype (all P > 0.05). Conclusion BDNF G196A gene rs6265 polymorphism is not associated with the cognitive function but with the clinical symptoms of schizophrenia.