Embden-Meyerhof Pathway Defects
(See also Overview of Hemolytic Anemia.)
Embden-Meyerhof pathway defects are autosomal recessive RBC metabolic disorders that cause hemolytic anemia.
The most common defect is
Other defects that cause hemolytic anemia include deficiencies of
In all of these pathway defects, hemolytic anemia occurs only in homozygotes. The exact mechanism of hemolysis is unknown. Symptoms are related to the degree of anemia and may include jaundice and splenomegaly. Spherocytes are absent, but small numbers of irregularly shaped spheres may be present.
In general, assays of ATP and diphosphoglycerate help identify any metabolic defect and localize the defective sites for further analysis.
There is no specific therapy for these hemolytic anemias. Most patients require no treatment other than supplemental folate 1 mg po once/day during acute hemolysis. In severe cases, patients may be transfusion dependent in which case, splenectomy may be done. Hemolysis and anemia persist after splenectomy, although some improvement may occur, particularly in patients with pyruvate kinase deficiency.