Erythropoietic porphyria

Erythropoietic porphyria (Orphanet code 659681) is a group classification encompassing porphyrias that primarily originate from defects in heme biosynthesis within erythroid (red blood cell) precursors in the bone marrow. This grouping includes conditions such as erythropoietic protoporphyria (EPP), X-linked protoporphyria (XLP), and congenital erythropoietic porphyria (CEP, also known as Günther disease). These disorders share the common feature of excessive accumulation of porphyrins or porphyrin precursors in red blood cells and other tissues, leading to characteristic clinical manifestations. The hallmark symptom across erythropoietic porphyrias is severe photosensitivity — patients experience intense pain, burning, swelling, and redness of the skin upon exposure to sunlight or visible light. In congenital erythropoietic porphyria, more severe cutaneous manifestations can occur, including blistering, scarring, skin fragility, and mutilating skin damage. Hemolytic anemia is also a common feature, particularly in CEP. The skin, hematologic system, and liver are the primary organ systems affected. Some patients may develop hepatic complications including liver dysfunction and gallstones due to porphyrin accumulation. Treatment approaches vary depending on the specific subtype. Strict sun avoidance and photoprotection remain the cornerstone of management for all erythropoietic porphyrias. For erythropoietic protoporphyria, afamelanotide (an alpha-melanocyte-stimulating hormone analogue) has been approved to increase light tolerance. For severe congenital erythropoietic porphyria, hematopoietic stem cell transplantation may be curative. Supportive measures include blood transfusions for anemia, monitoring of liver function, and in some cases, bone marrow transplantation. Gene therapy approaches are under investigation for certain subtypes.

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