This effect is especially devastating in cells that lack mitochondria, because these cells must use anaerobic glycolysis as their sole source of energy because the TCA cycle is not available. For example, red blood cells, which in a state of pyruvate kinase deficiency, rapidly become deficient in ATP and can undergo hemolysis. Therefore, pyruvate kinase deficiency can cause chronic nonspherocytic hemolytic anemia (CNSHA).[19]