A 41-year-old woman comes to the GP for 4-month history of progressive blistering lesions on the backs of her hands. She drinks 3 beers nightly after returning home from work at a rifle factory. Physical examination shows hyperpigmented skin and blisters in sun-exposed areas. Laboratory studies show elevated ALT and AST. Hemoglobin is 15 g/dL. MCV is 90 fL. Urinary uroporphyrin is detected. Which of the following is the most likely explanation for this patient’s findings?
Deficiency of δ-ALA synthase; valine is precursor; alcohol-induced
Deficiency of δ-ALA synthase; succinyl-CoA is precursor; B6 required
Deficiency of δ-ALA dehydratase; glycine is a precursor
Deficiency of porphobilinogen deaminase; valine is precusor
Deficiency of porphobilinogen deaminase; succinyl-CoA is precursor
Deficiency of uroporphyrinogen decarboxylase; glycine is precursor
Inhibition of ferrochelatase
