Hepatoerythropoietic porphyria: an autosomal recessive disorder in which there is a deficiency or absence of uroporphyrinogen decarboxylase; results in photosensitivity and excessive hepatic production of 8- and 7-carboxylate porphyrins. Source: Stedman's Medical Spellchecker, © 2006 Lippincott Williams & Wilkins. All rights reserved. Hepatoerythropoietic porphyria: An autosomal recessive cutaneous porphyria that is due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in both the LIVER and the BONE MARROW. Similar to PORPHYRIA CUTANEA TARDA, this disorder is caused by defects in the fifth enzyme in the 8-enzyme biosynthetic pathway of HEME, but is a homozygous enzyme deficiency with less than 10% of the normal enzyme activity. Cutaneous lesions are severe and mutilating.