Urinary excretion of position isomers of penta-and hexa-carboxylated porphyrins belonging to the isomer III series in a case of congenital erythropoietic porphyria.

The excretion of position isomers of penta- and hexa-carboxylated porphyrins type III in the urine in a case of congenital erythropoietic porphyria characterized by the excretion of large amounts of penta-, hexa- and hepta-carboxylated porphyrins type III together with isocoproporphyrins both in the urine and faeces, and a simple method for the synthesis and separation of such position isomers has been described. The implications of the finding of position isomers type III have been discussed and it is suggested that the decarboxylation of uroporphyrinogen III both in the present case and under physiological conditions is a random process.