experts in action

What's UP Doc? How many people have porphyria

  • May 6, 2022
  • What's UP Doc
  • Dr. Brendan McGuire


What's UP Doc? Is a monthly column where we feature a patient question along with a response from a member of the UPA Scientific Advisory Board.

Do you have a question you would like to ask a Porphyria Expert?  Send us an email at We’d love to hear from you!

I understand that Porphyria is a rare disease and being recently diagnosed with AIP, I am trying to understand more and more. How many people in the US have porphyria? Which type of porphyria is the most common? The least common? How do you calculate these numbers?

For this week’s response, Dr. Brendan McGuire was able to answer a newly diagnosed patient’s question. We are lucky to have Dr. McGuire as a member of our Scientific Advisory Board.

Porphyria is a very rare group of diseases, with only a couple thousands of people affected in the United States. Porphyria Cutanea Tarda (PCT) was always considered the most common type, but with the benefit of medications to cure hepatitis C, the rates of PCT are declining. Currently Acute Intermittent Porphyria (AIP) is the most common type, while Aminoleuvulinic Acid Dehydratase (ALAD) Deficiency the least common. We use data collected from our longitudinal database to calculate these numbers. To get more accurate accounts we encourage all patients with porphyria to enroll in our longitudinal database or with the United Porphryias Association.

To enroll into the Longitudinal Study, contact us at 800.868.1291 so we can connect you with a Coordinator.