Cutaneous porphyria in a neonate with tyrosinaemia type 1.

UNLABELLED: A term infant born to consanguineous parents presented at birth with hypoglycaemia, thrombocytopenia, coagulopathy and hyperbilirubinaemia associated with polycythaemia due to delayed cord clamping. Despite phototherapy and correction of polycythaemia by partial exchange transfusion, coagulopathy, hypoglycaemia and conjugated hyperbilirubinaemia persisted, suggesting hepatic failure. Metabolic work-up led to the diagnosis of tyrosinaemia type 1 on day 4. Two--(2-nitro-4-trifluoromethylbenzoyl)--1,3 cyclohexanedione (NTBC) treatment, started on day 5, resulted in progressive clinical improvement and unambiguous biochemical response. Severe skin purpuric lesions occurred in areas exposed to phototherapy. These resolved slowly after its discontinuation. Urine analysis sampled just before and 6 days after starting NTBC treatment showed high levels of type 1 coproporphyrin isomers. Such findings do not seem directly related to tyrosinaemia type 1 where succinylacetone inhibits delta-aminolevulinic acid (delta-ALA) dehydratase and where the accumulation of delta-ALA results in neurotoxicity without photosensitivity.

CONCLUSION

We describe a cutaneous form of porphyria in a neonate presenting with severe liver failure due to tyrosinaemia type 1. This porphyria is tentatively attributed to a secondary accumulation of coproporphyrins due to cholestasis, as reported in the bronze baby syndrome and recently described in neonates with purpuric phototherapy-induced eruption, rather than to a primary defect of porphyrin metabolism. The hypothesis of a direct effect of tyrosinaemia type 1 on porphyrin excretion is also discussed.