AGE-DEPENDENT REFERENCE VALUES OF URINARY PORPHYRINS IN CHILDREN

To establish age-dependent reference ranges for the 3 major urinary po rphyrins, uroporphyrin, coproporphyrin I and coproporphyrin III, conce ntrations were measured in random urine specimens from 198 children ag ed 0.5 to 16 and 18 new-borns by HPLC. All three porphyrins displayed unique age-dependencies. The highest coproporphyrin I concentration wa s observed in the new-born period, which could be explained by a physi ologically under-developed excretion system (via bile and faeces) for this particular porphyrin. Coproporphyrin LII excretion reached its hi ghest value in children between ages 1 and 2. Of the three porphyrins, coproporphyrin III concentration showed the closest correlation with the total haem synthesis in childhood. A relatively broad concentratio n range was found for uroporphyrin in all tested age-groups, the highe st mean concentration being in the new-born period. Quantification of each individual urinary porphyrin enables the diagnosis of certain dis orders which otherwise cannot be achieved by the total porphyrin deter mination. As an example of the clinical application of these reference ranges, a case of bronze baby syndrome is discussed.