Submitted April 30, 2007
Accepted August 18, 2007
Erythropoiesis and iron metabolism in dominant erythropoietic protoporphyria
S Alexander Holme, Mark Worwood, Alexander V Anstey, George H Elder, and Michael N Badminton*
Department of Dermatology, Cardiff University, Cardiff, Wales, United Kingdom
Department of Haematology, Cardiff University, Cardiff, Wales, United Kingdom
Department of Medical Biochemistry and Immunology, Cardiff University, Cardiff, Wales, United Kingdom
* Corresponding author; email: badmintonmn{at}cardiff.ac.uk.
Erythropoietic protoporphyria (EPP) results from deficiency of ferrochelatase (FECH) Accumulation of protoporphyrin IX causes life-long acute photosensitivity. Microcytic anemia occurs in 20-60% of patients. We investigated 178 patients with dominant EPP confirmed by molecular analysis. Erythropoiesis was impaired in all patients; all had a downward shift in hemoglobin (Hb), the mean being decreased in males by 1.2g/dL. By WHO criteria, 48% of women and 33% of men were anemic. Iron stores, assessed by serum ferritin (sFn), were decreased by two-thirds but normal serum soluble transferrin receptor-1 and iron concentrations suggested that erythropoiesis was not limited by iron supply. FECH deficiency in EPP appears to lead to a steady state in which decreased erythropoiesis is matched by reduced iron absorption and supply. This response may in part be mediated by protoporphyrin but we found no correlation between erythrocyte protoporphyrin and Hb, sFn, total iron binding capacity or transferrin saturation.
