Nitric oxide and the clinical manifestations of acute porphyria.

The porphyrias comprise a clinically and genetically heterogenous group of diseases mostly arising from a genetically determined dysfunction of specific enzymes along the pathway of haeme biosynthesis. This leads to a pathological accumulation and measurable excretion of porphyrins and/or porphyrin precursors, which is considered the cause of the clinical features related to this group of diseases. However, acute porphyria can present with varied symptoms, which have some features in common with other diseases where nitric oxide has been shown to play a role. The article describes the possibility of nitric oxide depletion in porphyria contributing to its clinical manifestations.