Porphyrias

Abstract

The porphyrias are a group of inherited disorders of heme biosynthesis [1, 2]. Each enzyme defect (Table 1) produces a specific pattern of overproduction of intermediates of the pathway, associated with characteristic clinical features. Porphyrias are classified as erythropoietic or hepatic, depending on the main site of overproduction. Most porphyrias are caused by partial enzyme defects, resulting in approximately 50% of normal activity, and are inherited as autosomal dominant traits. Exceptions are the rarer congenital erythropoietic porphyria and Doss porphyria (DP), with autosomal recessive inheritance and profoundly decreased enzyme activity.