No association between the brain-derived neurotrophic factor 196 G>A or 270 C>T polymorphisms and Alzheimer's or Parkinson's disease.

The brain-derived neurotrophic factor (BDNF) promotes survival, differentiation and maintenance of neurons in the central nervous system. BDNF 196 G>A and 270 C>T polymorphisms have previously been associated with Alzheimer's disease (AD) and with Parkinson's disease (PD). To study the role of BDNF 196 G>A and 270 C>T polymorphisms in Finnish AD and PD patients we genotyped BDNF 196 G>A and 270 C>T polymorphisms in 97 sporadic AD patients, 52 PD patients and 101 control subjects with polymerase chain reaction. No associations were found between the genotypes studied and AD or PD in Finnish patients. Moreover, no interaction between either BDNF polymorphism and the epsilon 4 allele of apolipoprotein E was found. In conclusion, it seems that the BDNF gene does not contribute significantly to the risk of AD or PD in Finnish patients.