Congenital Erythropoietic Porphyria with Persistent Severe Biochemical Abnormalities and a Non-Mutilating Clinical Course: A Case Report

Background and Clinical Significance: Congenital erythropoietic porphyria (CEP), also known as Günther disease, is a rare autosomal recessive porphyria caused by a deficiency of uroporphyrinogen III synthase, leading to the accumulation of phototoxic type I porphyrins. CEP classically presents in infancy with severe photosensitivity, blistering, scarring, and hemolytic anemia; however, significant phenotypic variability has increasingly been recognized. Case Presentation: We report a 32-year-old woman diagnosed with CEP in early infancy who demonstrated persistently and profoundly elevated erythrocyte porphyrin levels over more than a decade, yet who followed a relatively non-mutilating clinical course. Genetic testing identified a low-penetrance intronic UROS variant typically associated with erythropoietic protoporphyria, underscoring diagnostic challenges and genotype–phenotype discordance. The patient experienced marked improvement in photosensitivity and burning pain after initiation of afamelanotide, without the need for transfusion therapy or stem cell transplantation. Conclusions: This case highlights the heterogeneity of CEP, the importance of long-term biochemical follow up, and the potential role of afamelanotide in improving quality of life for selected patients with CEP.