Porphyria. Basic science aspects.

The porphyrias are a heterogeneous group of clinical disorders that share a common etiologic background in that each manifests a major metabolic defect in the synthesis of heme. The porphyrias represent an important category of human disease, perhaps as much for what they can teach us about how metabolic abnormalities are translated into clinical manifestations as they are as diseases per se. In this discussion an effort is made to describe, in some detail, the metabolic steps involved in the synthesis of heme and to correlate known abnormalities in this sequence of reactions that are associated with human porphyria.