Given the role of cGP in regulating IGF-1 function, we evaluated the changes in cGP, IGF-1, and IGFBP-3 concentrations in plasma and brain tissues, as well as their association with clinical outcomes in patients with metabolic hypertension, stroke, age-related cognitive impairment, PD, and AD. This evidence concerns the gene IGFBP3 and Parkinson disease.