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.