Several trials point toward an advantageouseffect of leptin on Alzheimer’s disease (AD) by enhancing cognitiveand learning functions.22 Therefore, mostof the neurological effects associated with leptin are currently beingtested in other neurodegenerative diseases, such as Parkinson’sdisease,23 to have robust experimentalevidence of the potential therapeutic role of leptin. This evidence concerns the gene LEP and early-onset autosomal dominant Alzheimer disease.