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Study of a kindred with hereditary spherocytosis and glyceraldehyde-3-phosphate dehydrogenase deficiency
Insights
Hereditary spherocytosis (HS) patients with glyceraldehyde-3-phosphate dehydrogenase (G3PD) deficiency showed no increased disease severity. However, combined G3PD deficiency and HS red blood cells exhibited signs of metabolic stress.
Area of Science:
- Hematology
- Biochemistry
- Genetics
Background:
- Hereditary spherocytosis (HS) is a genetic hemolytic anemia.
- Glyceraldehyde-3-phosphate dehydrogenase (G3PD) deficiency is a rare red blood cell enzyme defect.
Observation:
- Electrophoresis identified G3PD deficiency in an HS patient.
- Family studies revealed varying combinations of HS and G3PD deficiency.
Findings:
- G3PD deficient individuals were likely heterozygous with half-normal enzyme levels.
- G3PD deficiency alone was asymptomatic.
- Combined HS and G3PD deficiency did not worsen HS clinical severity.
- Combined G3PD deficiency and HS increased protein band 4.5, indicating metabolic stress.
Implications:
- G3PD deficiency does not exacerbate hereditary spherocytosis.
- Combined HS and G3PD deficiency reveals red blood cell metabolic stress.
- PAGE SDS is a valuable tool for diagnosing red blood cell enzyme deficiencies and associated membrane changes.
Abstract:
A patient with hereditary spherocytosis (HS) was found to have glyceraldehyde-3-phosphate dehydrogenase (G3PD) deficiency by electrophoresis of the isolated red cell membranes on polyacrylamide gels with sodium dodecyl sulfate (PAGE SDS) as demonstrated by a diminished band 6 (G3PD) and confirmed by specific enzyme assay. Thirteen members of his family were studied: four were normal, two had HS alone, three had G3PD deficiency alone, and four had both HS and G3PD deficiency. G3PD deficient kindred members were probably heterozygous, since their red cell enzyme, while qualitatively normal, was present in half normal amounts. The G3PD deficiency alone was asymptomatic, and there was no evidence that the combination of HS with G3PD deficiency increased the clinical severity of the disease. However, G3PD deficiency, when combined with HS, was associated with an increase in protein band 4.5 on PAGE SDS. This band was also increased by incubation of normal red cells without glucose, and appeared to be a protein absorbed to the membrane as a consequence of metabolic stress. Hence, red cells with the combined abnormalities of both HS and G3PD deficiency showed signs of the exceptional metabolic stress to which they were exposed.