Only six drugs are approved by the United States Food and Drug Administration (FDA) for the treatment of symptoms of AD: four acetylcholinesterase inhibitors (tacrine, donepezil, galantamine and rivastigmine), an N-methyl-D-aspartate receptor antagonist (NMDA) (memantine) and a fixed combination of donepezil and memantine [20,21,22]. The gene discussed is ACHE; the disease is Alzheimer disease.