The altered mGluR5 expression in astrocytes, which can affect intracellular Ca2+ signalling, is accompanied by augmented levels of S100β, as S100β protein exhibits a persistent over-expression in the hippocampus and in temporal, frontal and occipital lobes of DS foetuses, infants, children and adults (Griffin et al., 1998, Griffin et al., 1989, Jørgensen et al., 1990, Mito and Becker, 1993). Here, GRM5 is linked to Dravet syndrome.