alpha-ketoglutarate reductase deficiency (medical condition): A rare genetic disorder where the body lacks enzymes (lysine ketoglutarate reductase and saccharopine dehydrogenase) to metabolize lysine which then causes a harmful builds up of lysine in the blood and urine and saccharopins in the urine. Some patients are asymptomatic while others have severe symptoms. See also Hyperlysinemia, persistent