Associations between brain-derived neurotrophic factor G196A gene polymorphism and clinical phenotypes in schizophrenia patients

Background: Brain-derived neurotrophic factor (BDNF) had been chosen as a candidate gene for schizophrenia. This study investigated the relationships between BDNF G196A gene polymorphism and clinical phenotypes in schizophrenia patients in the Taiwanese population. Methods: During a one year period, 132 schizophrenic patients and 103 healthy controls were recruited. Psychiatric diagnoses were made according to DSM-IV criteria. Genotyping of the G196A polymorphism of BDNF was performed by polymerase chain reaction amplification and restriction fragment length polymorphism. Results: The data showed that the BDNF G196A genotypes and their allele distributions did not differ between patients with schizophrenia and healthy controls. No significant differences were noted in the BDNF G196A genotypes and allele distribution between schizophrenia patients with and without a family tendency for schizophrenia or between those with an age of onset before or after 25 years old. However, there was a significant difference in BDNF G196A genotype distribution between schizophrenia patients with and without a suicide history. Conclusions: These analytical results suggest that BDNF G196A gene polymorphism is associated with a susceptibility to a suicide history in schizophrenia patients in the Taiwanese population. Further study with a larger number of samples is needed to prove these findings.