AGT and Cognitive impairment: We genotyped single nucleotide polymorphisms (SNPs) in angiotensinogen (AGT: rs699, rs4762), angiotensin II receptors (AGTR1: rs5186 and AGTR2: rs5194, rs1403543) genes, as well as insertion/deletion polymorphism in the angiotensin-converting enzyme (ACE I/D) gene in 256 PD patients, divided into three groups: without cognitive decline, with mild cognitive impairment and with PD dementia.