Thus, while most of genes coding for glutamate receptor subunits increased their expression in epilepsy (GRIA1, GRIA3, GRIA4, GRIK3, GRIK4, GRIK5, GRIN2B, GRIN3A, GRM1, GRM7, and GRM8), few were downregulated (GRIA2, GRIA3, GRIN2A, GRM5, GRIK1, and GRIK2) (Fig. 4b, c). This evidence concerns the gene GRM5 and epilepsy.