Congenital erythropoietic porphyria. The effect of light shielding.

Abstract

SummaryThe effect of various types of measures taken for light shielding against daylight in a recently detected case of CEP, has been followed for more than a year. It has been found that the celluloid film, “Para‐Sol”, which has a good translucency for wavelengths above 550 nm, but is not translucent to wavelengths below 510 nm, not only removes the troublesome skin lesions seen in this disease, but also. brings about an almost complete compensation of the anemia, disappearance of the splenomegaly and marked changes in the blood and urinary porphyrin patterns. In blood the erythrocyte porphyrins change from predominantly proto‐porphyrin with trace amounts of copro‐ and not detectable uroporphyrin, to high amounts of both proto‐, copro‐ and uroporphyrins. The plasma porphyrins remain essentially unchanged. The urinary pattern changes from predominantly free porphyrins to predominantly porphyrinogens.It is suggested that the present case of congenital erythropoietic porphyria represents a new type of CEP, and that the hemolytic anemia with splenomegaly seen in CEP is due not to the inborn error itself, but to its tissue location and photochemical effect of light of wavelengths below 510 nm, when the porphyrin/porphyrinogen‐rich erythrocytes are exposed to daylight in the skin, while the skin lesions have been shown to depend primarily on the presence of an increase in the amounts of porphyrin/porphyrinogen in plasma. Cattle and the species Sciurus niger are mentioned as examples of species in which the light‐shielding effect of the fur has allowed the CEP‐gene to spread.