|Values are valid only on day of printing.|
Deficiencies of most of the enzymes of the Embden-Meyerhof (glycolytic) pathway, including pyruvate kinase (PK), have been reported. PK deficiency, although rare, is the erythrocyte enzyme deficiency most frequently found to be a cause of congenital nonspherocytic hemolytic anemia. It is an autosomal recessive disorder. Thus, the parents of affected patients are heterozygotes. Patients usually present during early childhood with anemia, icterus, and splenomegaly. Hemolytic disease of the newborn is common in persons with PK deficiency.
Work-up of cases of nonspherocytic hemolytic anemia
Investigating families with pyruvate kinase deficiency to determine inheritance pattern and for genetic counseling
Most pyruvate kinase (PK) deficient patients have 5% to 25% of normal activity.
Elevated PK concentrations can be found in those patients with younger erythrocyte population. This may be due to the patient being a newborn or young red cells are being produced in response to the anemia (reticulocytosis).
Because leukocytes also contain pyruvate kinase (PK) that is not diminished in hereditary erythrocytic PK deficiency, freeing the blood of white blood cells is always critical to this test.
> or =12 months: 6.7-14.3 U/g Hb
Reference values have not been established for patients who are <12 months of age.
Beutler E: Hereditary nonspherocytic hemolytic anemia: pyruvate kinase deficiency and other abnormalities. In Hematology. Fourth edition. Edited by WJ Williams, E Beutler, AJ Erslev, MA Lichtman. New York, McGraw-Hill Information Services Company, Health Professions Division, 1990, pp 606-612