GLUCOSE-6 –PHOSPHATE DEHYDROGENASE DIFICIENCY ANAEMIA (G6PD)

• Hereditary disorders of red cell interior are of 2 types-

1. Red cell enzyme defects (enzymopathies)

• Defective red cell metabolism involves 2 pathways-

1. Defect in hexose monophosphate shunt- E.g. G6PD deficiency.
2. Defect in Embden- Meyerhoff pathway- E.g. Pyruvate kinase deficiency

2. Disorders of haemoglobin (Haemoglobinopathies) 

G6PD-

• G6PD gene is located on the X- chromosome & its deficiency.
• Sex- linked trait affecting males and femal are carriers.
• Normal G6PD variant- Type B & Type A+
• Most common & significant variant A- type found in dark males.
• A- type G6PD variant protects against malaria.
• Abnormal protein folding leads to G6PD loss.
• Haemolytic attacks due to oxidant stress-

1. Drugs- antimalarial (Pyrimaquine), sulphonamides, vitamin K.
2. Ingestion of Fava beans (favaism)
3. Infections

Pathogenesis-

• In G6PD deficient cells oxidant will denature globin of haemoglobin to form Heinz bodies.
• To detect Heinz bodies stain, crystal violet is used.
• Macrophage will remove Heinz bodies & bite cells are formed.

Clinical features-

• Acute haemolytic anaemia
• Acute renal failure
• Neonatal jaundice

Lab findings-

1. During period of acute haemolysis,

• Rapid fall in haematocrit value.
• Formation of Heinz bodies is visualized by crystal violet called Heinz body haemolytic anaemia.

2. Between the crises- red cell survival is short.

 Diagnosis–

• MRT, Fluorescent screening test, ascorbate cyanotic screening test.
• Direct enzyme assay in red cells.

Treatment-

• Prevention of haemolytic anaemia
• Blood transfusion rarely.

Don’t Forget to Solve all the previous Year Question asked on Glucose-6 -phosphate dehydrogenase deficiency (G6PD)