[Late cutaneous porphyria in a child with Down's syndrome (author's transl)].

The authors report the case of a patent form of cutaneous or late porphyria in a 4 1/2 year-old child with a reduced activity of the erythrocyte uroporphyrinogene decarboxylase (URO D). This genetically transmitted disease (the father having the same enzyme defect) only appears after the occurrence of an external factor, usually alcohol and estrogens, rarely acute hepatitis with the presence of HAV antibodies as in this case of Down's syndrome. The same clinical picture may be accompanied by various hepatic lesions and, occasionally, by a deficiency of erythrocyte URO D. This justifies that one distinguish generalized familial forms from sporadic forms with exclusive hepatic involvement.