What is Porphyria Cutanea Tarda (PCT)?

• PCT is an acquired and familial disorder in which activity of the heme synthetic enzyme uroporphyrinogen decarboxylase (UROD) is deficient • Approximately 80% of all cases of PCT are acquired. 20% are familial, although the ratio may vary among different geographic regions and ethnic groups • Familial PCT most often arises from autosomal dominant inheritance of a single mutation of the UROD gene. Human UROD has been mapped to band 1p34. A rare recessive familial type of porphyria cutanea tarda in which both UROD alleles are mutated is termed hepatoerythropoietic porphyria • Familial PCT without detectable UROD mutations has been reported