In the literature, there is evidence regarding the role of MAPK-signaling, long-term depression, Hedgehog signaling, GnRH signaling, melanogenesis, T cell receptor pathways, cancer, vascular smooth muscle cells and hypertrophic cardiomyopathy (HCM) on cognitive function, Alzheimer’s, Parkinson's and Huntington’s diseases, and age-related neurodegenerative disorders [19, 27–34]. The gene discussed is GNRH1; the disease is Parkinsonism.