Phosphoglucose isomerase (PGI) deficiency presents with hemolytic anemia without hypoglycemia. The hemolysis occurs because RBCs depend exclusively on which pathway for ATP, and PGI deficiency traps glucose-6-phosphate upstream?

• A HMP shunt producing NADPH
• B Glucuronic acid pathway
• C Embden-Meyerhof glycolysis producing ATP ✓
• D Galactose oxidation pathway

Explanation

Mature RBCs lack mitochondria and depend entirely on the Embden-Meyerhof (anaerobic) glycolytic pathway for ATP production. PGI converts G6P to fructose-6-phosphate; its deficiency blocks glycolytic flux, depleting ATP in RBCs causing membrane failure and hemolysis. There is no hypoglycemia because the liver, which has the complete metabolic toolkit, compensates readily.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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