Porphyria cutanea tarda : some clinical and biochemical aspects

In this thesis we have reviewed the literature on the disease PCT and HCB-induced porphyria. PCT is a disorder of the heme synthesis pathway, which leads to accumulation of uroporphyrin and heptacarboxyl porphyrin and the excretion of very high levels of these two porphyrins in the urine. Similar metabolic findings are observed in HCB-porphyria, and HCB-induced porphyria has been used by many researchers as an animal model of PCT, to obtain insights into the pathogenesis of PCT. Our first studies were on the enzymatic changes in human PCT. PCT, although generally a disease of adulthood, appears in some instances to have a genetic background, and the familial occurrence of PCT was described many years ago. The inherited enzymatic defect in these families is a reduction in URO-D activity. We developed a simple method to evaluate URO-D status in family studies