In the central nervous system (CNS), progesterone has been demonstrated to exert a neuroprotective effect through the hormone receptor PGRMC1 (Progesterone receptor membrane component 1), but it has also been established that PGRMC1 binds to Aβ oligomers in AD brain tissue, mediating the possible synaptotoxicity effects of Aβ. The gene discussed is PGRMC1; the disease is Alzheimer disease.