Uroporphyrinogen decarboxylase gene mutations in Danish patients with porphyria cutanea tarda.

Decreased uroporphyrinogen decarboxylase (UROD) activity is a characteristic feature of the most common of the porphyrias, porphyria cutanea tarda (PCT). A subgroup of the clinically overt PCT cases is associated with mutations in the gene encoding UROD and inherited as an autosomal-dominant trait. In this study, DNAs from 53 Danish PCT patients were subjected to genetic analysis for UROD mutations using denaturing gradient gel electrophoresis. Eleven genetic variations, seven of which are possible disease causing, were identified. All but one of these mutations were previously unknown, lending further support to the assumption that PCT is a heteroallelic disease. Only 11% of the examined patients were previously recognized as familial PCT cases. However, possible disease-related UROD mutations were identified in 24% of the examined patients, indicating that genetic analysis of PCT patients may improve differentiation between familial and sporadic PCT cases.