A 28-year-old man presents with recurrent episodes of severe abdominal pain, tachycardia, and vomiting. Between episodes he has developed blistering skin lesions on sun-exposed areas. Urine shows elevated porphobilinogen during acute attacks. Which enzyme is deficient?
- A Protoporphyrinogen oxidase ✓
- B Uroporphyrinogen decarboxylase
- C Porphobilinogen deaminase
- D Ferrochelatase
Correct answer: A. Protoporphyrinogen oxidase
Explanation
Variegate porphyria is caused by protoporphyrinogen oxidase deficiency. It is a mixed porphyria presenting with both acute neurovisceral attacks (abdominal pain, autonomic instability, elevated PBG) AND cutaneous photosensitivity with blistering. AIP has neurovisceral symptoms but no skin lesions. PCT has skin lesions but no neurovisceral attacks. EPP causes non-blistering photosensitivity without neurovisceral features.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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