Two classes of drugs for dementia treatment have been approved by the major regulatory agencies (US Food and Drug Administration, FDA; European Medicines Agency, EMA; Pharmaceuticals and Medical Devices Agency, PMDA): acetylcholinesterase inhibitors, which treat mild to moderate Alzheimer's disease (AD), and N-methyl-D-aspartate receptor antagonists (e.g., memantine), which treat moderate to severe AD. This evidence concerns the gene ACHE and Alzheimer disease.