Mondo Description Hepatoerythropioetic porphyria (HEP) is a very rare form of chronic hepatic porphyria characterized by bullous photodermatitis.

Uniprot Description A form of porphyria. Porphyrias are inherited defects in the biosynthesis of heme, resulting in the accumulation and increased excretion of porphyrins or porphyrin precursors. They are classified as erythropoietic or hepatic, depending on whether the enzyme deficiency occurs in red blood cells or in the liver. HEP is a cutaneous porphyria that presents in infancy. It is characterized biochemically by excessive excretion of acetate-substituted porphyrins and accumulation of protoporphyrin in erythrocytes. Uroporphyrinogen decarboxylase levels are very low in erythrocytes and cultured skin fibroblasts.