First, we only explored the association between BDNF Val66Met SNP and cognitive impairments in PD patients; however, it is unknown whether other BDNF SNPs such as rs11030104 and rs7103411 could be involved in BNDF plasma Levels and cognitive defects in PD patients (Han et al., 2015). The gene discussed is BDNF; the disease is Cognitive impairment.