Reduced ferrochelatase activity in fibroblasts from patients with porphyria variegata.
Ferrochelatase deficiency has been shown in both porphyria variegata (PV) and erythropoietic protoporphyria (EPP). It has been suggested that in PV there is a decrease in the enzyme, whereas in EPP the enzyme is unstable. In the present study ferrochelatase activity was measured in skin fibroblasts from three patients with PV and three normal subjects. The enzymatic activity in the patients with PV (17.5 +/- 4.5 pmoles heme formed per 10(7) fibroblasts per hour) was 50% of that of the control group (31.0 +/- 3.2 pmoles heme formed per 10(7) fibroblasts per hour). This supports the contention that the enzyme is deficient in PV and that an inactive ferrochelatase is the primary deficiency in this type of porphyria.