Mechanism of Disease
A Swedish study indicated that approximately 90% of cases of acute intermittent porphyria are due to a mutation that causes decreased amounts of the enzyme, and to a lesser degree by a mutation that causes decreased activity of each enzyme molecule.
Under normal circumstances, heme synthesis begins in the mitochondrion, proceeds into the cytoplasm, and finishes back in the mitochondrion. However, without porphobilinogen deaminase, a necessary cytoplasmic enzyme, heme synthesis cannot finish, and the metabolite porphobilinogen accumulates in the cytoplasm.
Additional factors must also be present such as hormones, drugs, and dietary changes that trigger the appearance of symptoms. Symptoms of AIP may include abdominal pain, constipation, and muscle weakness.
Patients with AIP are commonly misdiagnosed with psychiatric diseases. Subsequent treatment with anti-psychotics increases the accumulation of porphrobiliogen, thus aggravating the disease enough that it may prove fatal.
Read more about this topic: Acute Intermittent Porphyria
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