Acute intermittent porphyria (AIP) is a rare metabolic disorder affecting the production of heme resulting from a deficiency of the enzyme porphobilinogen deaminase.

The patients are typically asymptomatic, with most gene carriers having no family history because the condition had remained latent for several generations.

[6] A distinguishing feature of AIP that separates it from other porphyrias is the absence of photosensitive cutaneous symptoms that occur in addition to acute attacks.

[13] Hyponatremia is the most common electrolyte abnormality during acute attacks, occurring in 40% of patients and presenting as SIADH.

[citation needed] The most common identified triggers for acute attacks are medications, weight loss diets, and surgery.

In AIP, over 100 mutations have been identified on the long arm of chromosome 11 at the HMBS gene, which codes for the cytoplasmic enzyme porphobilinogen deaminase.

[24] The dominance pattern is a result of partial deficiencies from the heme biosynthesis enzymes, hydroxymethylbilane synthase (HMBS;  EC  2.5.1.61).

[25] Due to the rarity of this disease it is difficult to estimate the prevalence of AIP and the inclusion criteria differs widely among studies causing varying statistics.

[citation needed] The initial diagnosis of acute porphyria is confirmed by urinalysis, including the common method, the Watson-Schwartz test.

Elevated urine porphobilinogen confirms diagnosis of AIP, hereditary coproporphyria (HCP), or variegate porphyria (VP).

[citation needed] With advancement and increased accessibility to genetic testing and follow up counseling, the morbidity of AIP has decreased because of early diagnosis.

The combination of targeted mutation analysis and biochemical activity tracking have provided positive results for identifying the risk of AIP development.

Additionally, individuals who were diagnosed at the symptomatic stage encountered more mild attacks after diagnosis, although they still had symptoms.

Hot water baths or showers may lessen nausea temporarily, but can present a risk of burns or falls.

[28] Some benzodiazepines are safe, and, when used in conjunction with newer anti-seizure medications such as gabapentin, offer a possible regimen for seizure control.

[citation needed] One of the many hypothesized diagnoses of the artist Vincent van Gogh is that he and his siblings, in particular his brother Theo, had AIP and syphilis.

[29] Another theorized case was King George III of the United Kingdom[30] who even had a medallion struck to commemorate his "curing".