Pharmaceutical companies, including Novartis (Basel, Switzerland), AstraZeneca (Gaithersburg, MD, USA), Addex Pharmaceuticals (Sunrise, FL, USA) report advancing mGlu5 NAMs through phase I or II clinical trials for treating fragile X syndrome, L-DOPA-induced dyskinesias, neuropathic pain, migraine pain, and GERD. The gene discussed is GRM5; the disease is fragile X syndrome.