Acquired erythropoietic protoporphyria

Dear Editor,Porphyrias are a group of diseases characterized byaberrations in the heme biosynthetic pathway. They canbe classified according to the primary site of the enzymaticdefect (i.e., hepatic versus erythropoietic) or according totheir clinical presentation into acute versus chronic ornoncutaneous versus cutaneous forms. Among the cutane-ous porphyrias, erythropoietic protoporphyria (EPP) standsout as the only form characterized by an immediate painfulreaction to sunlight [ 1].We report a case of an acquired variant of EPPdeveloping in a patient with myelodysplastic syndromemost likely due to the genetic instability associated with thedisease.A 66-year-old Caucasian man presented for the evalua-tion of stinging –burning pain that developed immediatelyafter exposure to sunlight and was restricted to the exposedskin. The condition had started 4 years earlier and hadbecome so severe that the patient avoided direct sunlightcompletely. Densely woven fabrics but not sunscreens orwindow glass provided protection. On physical examina-tion, we found mild, waxy thickening with small, scar-likedepressions of the skin over the nose and the backs of thehands. The patient had been evaluated earlier for poly-morphic light eruption, solar urticaria, and lupus erythema-tosus without positive results. The patient's history wasremarkable for a myelodysplastic syndrome (myelodys-plastic syndrome –refractory anemia with ringed sidero-blasts) that had been diagnosed 4 years earlier at about thesame time when the skin symptoms had appeared. Anemiawas the leading symptom of the myelodysplastic syndromeand was treated with repeated erythrocyte substitution.Examination of native blood and bone marrow smearsrevealed autofluorescence of a large proportion of thepatient's red blood cells (Fig. 1). Biochemical analysisshowed increased levels of free erythrocyte protoporphyrin(241 µg/dl red blood cells, normal range C, 252 A > G) in the ferrochelatasegene together with a so far undescribed polymorphism(IVS2 + 169 G > A) in intron 2 [ 2, 3]. Larger deletionswere excluded by fluorescence in situ hybridizationanalysis. A diagnosis of acquired EPP was made and