Heme metabolism: porphyria: practice question

The best answer is C, Porphobilinogen deaminase. Acute intermittent porphyria results from porphobilinogen deaminase deficiency.

Ferrochelatase deficiency contributes to erythropoietic protoporphyria.

Uroporphyrinogen decarboxylase deficiency causes porphyria cutanea tarda with photosensitivity.

ALA dehydratase is inhibited by lead and is rarely deficient.

It tests Heme metabolism: porphyria in Biochemistry. Hepatic CYP induction worsens attacks, and accumulated intermediates produce neurovisceral symptoms without cutaneous photosensitivity.

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.