Mutations in pyruvate kinase.

Pyruvate kinase (PK) deficiency due to mutations of the PKLR gene is a common cause of hereditary nonspherocytic hemolytic anemia. Thus far, 55 different mutations have been described in patients with PK-deficient hemolytic anemia. Polymorphisms within the PKLR gene and in the tightly linked glucocerebrosidase (GBA) gene suggest that PK deficiency may represent a balanced polymorphism.