Patients with a diagnosis of AHP will be eligible for the study and will be managed and treated per routine clinical practice.

Selected events of interest are defined as hepatic events (including hepatic neoplasia), renal events, thromboembolic events, and pancreatitis.

Porphyria attacks are defined as meeting all of the following criteria: an acute episode of neurovisceral pain in the abdomen, back, chest, extremities and/or limbs, no other medically determined cause, and requires treatment with intravenous (IV) dextrose or hemin, carbohydrates, or analgesics, or other medications such as antiemetics at a dose or frequency beyond the participant's usual daily porphyria management.