The same group also found that both human FXS NPCs and Fmr1-KO mouse NPCs exhibited larger intracellular calcium release amplitudes in response to the group I mGluR (mGluR1 and mGluR5) agonist (S)-3,5-dihydroxyphenylglycine (DHPG) compared to controls and WTs, respectively [62]. This evidence concerns the gene GRM5 and fragile X syndrome.