Hypothalamic (including orexin immunoreactive neurons), thalamic, and brainstem regions involved in arousal, sleep, narcolepsy/cataplexy, reward processing, addictive and feeding behaviors, and autonomic and motor responses were explored in MMC children and young adults with AD, PD, FTLD, and ALS neuropathology hallmarks. The gene discussed is HCRT; the disease is Alzheimer disease.