* Compared with activity of normal red cells, residual activity may be much lower if it is related to reticulocyte-rich control.

† Measure by the backward reaction.

‡ Glycogen storage disease type VII (Tarui's disease), the muscular symptoms comprise mainly myopathy and severe muscle cramps; the disease may be fatal in infancy.

§ Increased infection; no significant improvement of hemolysis.

‖ Severe defects show spherocytes, elliptocytes, and red-cell fragments (schistocytes), and somewhat resemble hereditary spherocytosis.

Reprinted with permission from Handin et al.⁴³