We considered the monthly proportion of patients eligible for treatment, with a diagnosis of probable Alzheimer’s disease, receiving their first prescription for each drug class—namely, acetylcholinesterase (AChE) inhibitors (donepezil, rivastigmine, galantamine) and N-methyl-d-aspartate (NMDA) receptor antagonists (memantine). The gene discussed is ACHE; the disease is early-onset autosomal dominant Alzheimer disease.