Val66Met BDNF polymorphism is associated with Parkinson's disease cognitive impairment.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases worldwide. Besides characteristic PD motor features, the disease has important non-motor characteristics such as cognitive impairment. The role of genetic factors in cognitive impairment associated with PD is still unclear. In this study, we examined whether BDNF Val66Met was associated with impaired cognition in Parkinson's disease. One hundred and seventy five patients with a clinical diagnosis of Parkinson's disease were included. Global cognitive abilities of the patients were measured by the Mini-Mental State Examination (MMSE). Poisson Regression models were used to test for association between 66Met carriers and cognitive impairment controlling for covariates. Carriers of at least one BDNF 66Met allele presented a higher prevalence of cognitive impairment (p=0.005 RR=1.45 IC=95% [1.1-1.8]). These results suggest a role for BDNF Val66Met polymorphism on cognitive impairment in PD.