NRN1 and early-onset autosomal dominant Alzheimer disease: In this review, we summarize recent findings regarding neuritin’s signaling pathways, neuroprotective, neuroregenerative, and neuromodulatory properties, with a focus on its therapeutic potential to counter neurodegeneration in various conditions such as glaucoma, Alzheimer’s disease, stroke, diabetic neuropathy, and neuropsychiatric disorders.