Porphyria cutanea tarda - When skin meets liver

Porphyria cutanea tarda (PCT) is the most frequent type of porphyria worldwide and results from a catalytic deficiency of uroporphyrinogen decarboxylase (UROD) the fifth enzyme in heme biosynthesis At least two different types of PCT are currently distinguished an acquired variant also referred to as sporadic or type I PCT in which the enzymatic deficiency is limited to the liver and an autosomal dominantly Inherited form also known as familial or type II PCT in which there is a decrease of enzymatic activity in all tissues The cutaneous findings include Increased photosensitivity skin fragility blistering erosions crusts and miliae on the sun-exposed areas of the body Additionally hyperpigmentation hypertrichosis sclerodermoid plaques and scarring alopecia might be observed In patients with type I PCT there is a significant association with liver disease that can be triggered by genetic and environmental factors such as alcohol abuse iron overload haemochromatosis polychlorinated hydrocarbons and hepatitis C virus infection The diagnosis of PCT can be made based on the skin symptoms a characteristic urinary porphyrin excretion profile and the detection of isocoproporphyrin in the feces In red blood cells of individuals with type II PCT UROD activity is decreased by approximately 50% due to heterozygous mutations in the UROD gene Here we provide an update on clinical diagnostic and therapeutic aspects of PCT a disorder that affects both skin and liver (C) 2010 Elsevier Ltd All rights reserved