Acute intermittent porphyria

In most places, acute intermittent porphyria (AIP) is the most common of the acute hepatic porphyrias, which is a group of conditions with similar symptoms to AIP. In Europe (excluding Sweden), AIP occurs in about 0.13 in 1 million people per year. In Sweden, the rates are about 4 times higher. The number of people with latent AIP may be underestimated.