GRM1 and Alzheimer disease: Two studies have investigated the relationship between mGluR1 and AD; one study found increased expression of cerebral mGluR1 in a mouse model of AD (Ostapchenko et al., 2013) and the other found decreased expression of cerebral mGluR1 in postmortem brains with DLB accompanied by AD related-pathology (Albasanz et al., 2005).