Protoporphyria, x-linked dominant

Very rare, X-linked dominant inherited porphyria form ( OMIM 300752) with phototoxic skin reactions due to elevated protoporphyrin in erythrocytes and pathologically elevated plasma protoporphyrin in serum. As in erythropoietic protoporphyria, the clinical symptoms are triggered by short-wave visible and long-wave UVA light (window glass offers no protection).

• Urine: Normal color, protoporphyrin is elevated.
• Faeces: protoporphyrin is elevated, coproporphyrin is elevated.
• Erythrocytes: Orange-red fluorescence in the fluorescence microscope, which disappears after 10-15 seconds.
• Protoporphyrin is elevated in erythrocytes. The peculiarity that distinguishes this form from classical erythropoietic protoporphyria is the predominance of zinc chelated protoporphyrins (in erythropoietic protoporphyria the free fraction clearly predominates).

1. Frank J et al (2011) Hereditary metabolic diseases with cutaneous manifestation. Dermatologist 62: 98-106
2. Whatley Sd et al (2008) C-terminal deletions in the ALAS2-gene lead to gain of function and cause X-linked dominant protoporphyria without anemia or iron overload. At J Hum Genet 83: 408-414