Fmr1KO mice overexpress amyloid precursor protein (APP) through an mGluR5-dependent pathway [111], and the J20 mouse model of Alzheimer’s disease that over-expresses APP with familial mutations exhibits a deficit in REM sleep, which is rescued with the mGluR5 inhibitor CTEP. The gene discussed is APP; the disease is early-onset autosomal dominant Alzheimer disease.