Acute intermittent porphyria (
AIP) is a rare
autosomal dominant metabolic disorder affecting the production of
heme, the oxygen-binding prosthetic group of
hemoglobin. It is characterized by a deficiency of the
enzyme porphobilinogen deaminase. Acute intermittent porphyria is the second most common form of
porphyria (
porphyria cutanea tarda being the most common). Its incidence is estimated to be between 5 and 10 in 100,000, but this is likely underestimated because of positive cases not being induced, and long periods of latency, with an estimation that it is latent in 90% of cases.