Porphyrins in urine, plasma, erythrocytes, bile and faeces in a case of congenital erythropoietic porphyria (Gunther's disease) treated with blood transfusion and iron chelation: Lack of benefit from oral charcoal

Congenital erythropoietic porphyria is a rare genetic disorder in which def iciency of uroporphyrinogen III synthase results in excessive production of Type I porphyrins, The main clinical features are severe photodestruction of the skin and haemolytic anaemia. Treatment consists of shielding from li ght, blood transfusions and splenectomy, but is generally unsatisfactory. P revious studies have suggested that oral charcoal may be of benefit by bind ing porphyrins in the gut. A trial was therefore undertaken to evaluate thi s possibility. Porphyrins in urine, plasma and erythrocytes were measured by HPLC in a 23- year-old male patient with congenital erythropoietic porphyria, during an 8 week "run-in" period, and for a further 3 weeks when oral charcoal was giv en. Total urinary porphyrin excretion was 79-283 mu mo1/24 h consisting of 75% uroporphyrin I, 15% coproporphyrin I and smaller amounts of hepta-, hex a-, and pentacarboxylic porphyrins, Similar proportions were found in plasm a and erythrocytes, During the first 24 h of charcoal administration a mino r decrease in plasma and erythrocyte porphyrins was detected but this was n ot maintained during the remainder of the trial. In bile and faeces copropo rphyrin I constituted approximately 95% of the porphyrins, with 2-3% coprop orphyrin III and smaller amounts of pentaporphyrins I and III, but only tra ce amounts of uroporphyrin I. Oral charcoal was of no value in this case. Reasons are discussed in the co ntext of biochemical differences between this patient with classical Gunthe r's disease and the similar clinical syndrome due to deficiency of uroporph yrinogen decarboxylase, (C) 1998 John Wiley & Sons, Ltd.