A 32-year-old woman presents with abdominal pain, fever, and dark urine after eating fava beans. Labs show Hb 6.5 g/dL, reticulocytosis, Heinz bodies on supravital staining, and low glucose-6-phosphate dehydrogenase (G6PD) activity. Peripheral smear shows bite cells. Which enzyme deficiency is responsible, and what is the inheritance pattern?
- A Pyruvate kinase deficiency; autosomal recessive
- B Glucose-6-phosphate dehydrogenase deficiency; X-linked recessive ✓
- C Hexokinase deficiency; autosomal dominant
- D Glucose-6-phosphatase deficiency (von Gierke disease); autosomal recessive
Correct answer: B. Glucose-6-phosphate dehydrogenase deficiency; X-linked recessive
Explanation
G6PD deficiency is X-linked and causes oxidative hemolysis triggered by fava beans, infections, or drugs (primaquine, dapsone). Heinz bodies and bite cells are characteristic. Pyruvate kinase deficiency causes hereditary nonspherocytic hemolysis but is autosomal recessive and not triggered by fava beans. Hexokinase deficiency is rare. Glucose-6-phosphatase deficiency is glycogen storage disease type I.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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