Congenital 6‐phosphogluconate dehydrogenase (6PGD) deficiency associated with chronic hemolytic anemia in a Spanish family

Abstract

Clinical and metabolic studies were performed in four members of a Spanish family with partial (50%) 6 phosphogluconate dehydrogenase (6PGD) deficiency. In all cases the activities of 6 phosphogluconolactone (6PGL) and glutathione reductase (GR) were normal, and the molecular characterization performed in the partially purified 6PGD from the propositus showed normal kinetic and electrophoretic patterns. Two females (the propositus and her sister) suffered from a well-compensated chronic nonspherocytic hemolytic anemia (CNSHA) and exhibited decreased RBC glutathione (GSH) stability with increased oxidative susceptibility, defined by enhanced malonyldialdehyde (MDA) generation "in vitro." The other two members of the family (the propositus's mother and brother) were clinically asymptomatic. In the propositus and her sister, RBC metabolism exhibited a markedly abnormal concentration of glycolytic intermediates, mainly characterized by striking increases in fructose 1,6 bisphosphate (50-fold), dihydroxiacetone-phosphate (20-fold) and glyceraldehyde 3-phosphate (tenfold). Although the precise mechanism of the hemolysis in the two patients is unknown, the enhanced oxidative threat observed in their RBCs may interfere in some way with the glycolytic pathway function, leading to a marked increase in certain metabolic intermediates located before the glyceraldehyde 3 phosphate dehydrogenase (GA3PD) step. Since it seems that GA3PD half-life is modulated by fluctuations of the cytosolic redox status, an "in situ" approach was simulated by using permeabilized RBCs. In these conditions, GA3PD activity was significantly lower in the propositus and her sister than in the asymptomatic members of the family and the simultaneous normal control.

Expression of Glucose-6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase in Oxidative Stress Induced by Long-Term Iron Toxicity in Rat Liver

“…The deficiency of 6PGD is generally asymptomatic, and the inheritance of this disorder is autosomal dominant. Hemolysis results from the combined deficiency of 6PGD and 6-phosphogluconolactonase [16].…”

Isocitrate Dehydrogenase Is Important for Nitrosative Stress Resistance in Cryptococcus neoformans, but Oxidative Stress Resistance Is Not Dependent on Glucose-6-Phosphate Dehydrogenase

“…The pentose phosphate pathway is an essential factor in maintaining health of erythrocytes, cells that, due to their biological function, have considerable risk for oxidative damage. Humans deficient in the pathway have hemolytic anemia, as their erythrocytes are unable to maintain sufficient pools of reduced glutathione (68). Also, the pressure of oxidative stress can stimulate the pentose phosphate pathway.…”

Point Mutations That Reduce Erythrocyte Resistance to Oxidative Stress

“…The episodic hemolytic events with jaundice in patients with 6PGD deficiency may be the result of a defective erythrocytes ability to counteract conditions of marked oxidative stress as happens at birth and following traumatic events. The presence of 6PGD deficiency could be mistaken for a partial G6PD deficiency if the assay of G6PD activity was performed without correcting for 6PGD activity (Vives Corrons et al, 1996;Caprari et al, 2001). …”