[Homozygote erythropoietic protoporphyria associated with porokeratosis]

Erythropoietic protoporphyria was generally assumed to be an autosomal dominant disease with variable penetrance. The determination of the ferrochelatase activity and the biological molecular studies have shown that both autosomal dominant and recessive patterns of inheritance are possible.

Is reported the case of a 17 years-old male patient with erythropoietic protoporphyria and porokeratosis. There are some hepatic biochemical abnormalities without cholelithiasia and without pathological change of the liver biopsy. Leucocyte ferrochelatase activity is decreased to 5 p. 100 of the normal mean level. In both the parents, without photosensitivity, the enzyme activity is reduced to 40 p. 100 of the normal values.

The patients with severe ferrochelatase defect have no more important clinical manifestations than in the usual form of erythropoietic protoporphyria. For clarify the exact mode of inheritance, the determination of the ferrochelatase activity and the identification of the mutations in the patient and his parents are necessary. In our patient the porokeratosis should be in relation with the protoporphyrin induced phototoxic reaction which facilitate the emergence of a mutant cellular clone of epithelial cells.