Increased glutamate concentrations have been reported in the hippocampal region of people with autism using proton magnetic resonance spectroscopy [66], consistent with previous reports of increased serum levels of glutamate [67], giving rise to a hyperglutamate hypothesis of autism [68], which suggests in part that higher glutamate levels in autism may be due to reductions in GAD. The gene discussed is GAD1; the disease is autism.