Finally, there could also be functional effects on mGlu3 signalling in schizophrenia which are independent of receptor abundance, for example differences in heterodimerisation with other receptors (Gonzalez-Maeso et al., 2008, Doumazane et al., 2011), or the coupling of mGlu3 to G-proteins and other downstream effectors (Salah-Uddin et al., 2009). The gene discussed is GRM3; the disease is schizophrenia.