Porphyrias

A 35-year-old man from Delhi presents with a 6-month history of recurrent blistering and erosions on the dorsal surfaces of his hands and forearms. He reports photosensitivity and notices that lesions worsen in summer. On examination, he has hyperpigmentation, scarring, and alopecia on sun-exposed areas. Liver function tests reveal mild elevation of transaminases (AST 65 U/L, ALT 72 U/L). He admits to consuming alcohol daily for the past 10 years. Urine is dark brown and fluorescent under Wood's lamp. Which is the most likely diagnosis?

A 28-year-old woman from rural Maharashtra presents to the emergency department with severe abdominal pain, tachycardia (HR 110/min), and confusion. She reports a 3-day history of colicky abdominal pain, vomiting, and progressive neuropsychiatric symptoms including anxiety and hallucinations. Her sister was diagnosed with a similar condition 2 years ago. On examination, she is hypertensive (BP 160/95 mmHg) and has proximal muscle weakness. Urine dipstick is normal, but when left standing overnight, the urine turns dark red. Serum sodium is 125 mEq/L (hyponatremia). Which is the most likely diagnosis?

Which enzyme is deficient in acute intermittent porphyria (AIP)?