In normal conditions, NO production is tightly regulated, and high levels of NO due to increased neuronal NOS (nNOS) can trigger neuronal dysfunction by enhancing nitrosative stress, as observed in several neurodegenerative diseases, such as PD, Alzheimer’s disease (AD), Huntington’s disease (HD), and stroke [11]. Here, NOS1 is linked to early-onset autosomal dominant Alzheimer disease.