Porphyria, Acute Intermittent

**Definition:** An autosomal dominant porphyria that is due to a deficiency of HYDROXYMETHYLBILANE SYNTHASE in the LIVER, the third enzyme in the 8-enzyme biosynthetic pathway of HEME. Clinical features are recurrent and life-threatening neurologic disturbances, ABDOMINAL PAIN, and elevated level of AMINOLEVULINIC ACID and PORPHOBILINOGEN in the urine.

**Tree numbers:** - C06.552.830.150 - C16.320.850.742.150 - C17.800.827.742.150 - C18.452.811.400.150

**Synonyms:** - Acute Porphyria