Previous studies of AD patient brains have showed a decrease in glutamine synthase, as well as a marked decrease in phosphate-activated glutaminase levels and α-ketoglutarate dehydrogenase complex.2, 30, 31, 32, 33 Such changes could conceivably lead to disturbances in glutamate production and recycling in vivo. The gene discussed is GLUL; the disease is Alzheimer disease.