The principal neurotransmitter systems altered in patients with AD are cholinergic and glutamatergic systems, which are especially affected by neurodegeneration, which in turn, allowed for the development of acetylcholinesterase (AChE) inhibitors and antagonists of N-methyl-d-aspartate (NMDA) receptors, the main drugs employed to treat AD [5]. The gene discussed is ACHE; the disease is Alzheimer disease.