MECP2 and early-onset autosomal dominant Alzheimer disease: While trofinetide demonstrates neuroprotective effects and synaptic stabilization in Rett syndrome through IGF-1 pathway modulation, Rett syndrome pathogenesis (MECP2 mutations, transcriptional dysregulation) differs fundamentally from Alzheimer’s disease mechanisms (amyloid cascade, tauopathy, neuroinflammation).