Pyruvate kinase deficiency, also called erythrocyte pyruvate kinase deficiency, is an inherited metabolic disorder of the enzyme pyruvate kinase which affects the survival of red blood cellsBoth autosomal dominant and recessive inheritance have been observed with thedisorder; classically, and more commonly, the inheritance is autosomal recessive. Pyruvate kinase deficiency is the second most common cause of enzyme-deficient hemolytic anemia, following G6PD deficiency.