What is pyruvate kinase deficiency?

Caused by gene mutation affecting activity of pyruvate kinase (last enzyme in glycolysis turning phosphoenol pyruvate to pyruvate making ATP) Auto recessive, intrinsic to RBC, extravascular (spleen), since no pyruvate kinase, 1,3-bisphosphoglycerate will transform to 2,3-DPG which offsets anemia by right shifting the oxygen saturation curve