Cutaneous Hepatic Porphyria
Cutaneous hepatic porphyrias (CHP) are the most common form of porphyria. Patients present with cutaneous photosensitivity but do not experience attacks of neurovisceral dysfunction. The basic biochemical defect is reduced activity of the enzyme uroporphyrinogen decarboxylase (URO.D) in the liver, which results in overproduction and increased excretion of uroporphyrin and other polycarboxylated porphyrins. CHP differs from the other porphyrias in that there is no clear pattern of inheritance in the majority of cases, although in some familial transmission can clearly be established (Topi and D’Alessandro, 1977). Environmental factors play an important role. The cause of the reduced URO.D activity remains unclear but appears to be the result of complex interactions of both genetic and acquired factors (Mukerji et al., 1985b; Sweeney, 1986).
Unable to display preview. Download preview PDF.