Porphyrin synthesis in blood cells of patients with erythropoietic protoporphyria.

The protoporphyrin accumulation observed in the red blood cells of patients with erythropoietic protoporphyria can be explained by decreased activity of the enzyme heme synthetase or by increased production of porphyrins in the affected cells. In literature experimental evidence both for a partial heme synthetase deficiency and for increased porphyrin biosynthesis has been presented. In a group of ten patients with erythropoietic protoporphyria the biosynthesis of porphyrins from delta-aminolevulinic acid and from glycine-succinic acid appeared to be normal in peripheral blood cells. These results are consistent with the partial heme synthetase deficiency previously found to be the basic defect of this disease.