Relative analysis on mRNA expression revealed down regulations of GRM5 (33.33), GRM6 (3.13), GRM7 (3.85), GRIA1 (4.76), GRIN2A (4.76), GRIN2B (7.14) in the ADHD probands as compared to the controls (Fig. 4B). This evidence concerns the gene GRM5 and attention deficit-hyperactivity disorder.