[Activity of delta-aminolaevulinic acid (ALAD) in erythrocytes of patients with chronic hepatic porphyria (porphyria cutanea tarda)].

Erythrocyte delta-aminolaevulinic acid dehydratase (ALAD) activity was estimated in chronic hepatic porphyria, correlated with some tests of liver function and compared with enzyme activity in chronic liver diseases. 24 patients with chronic hepatic porphyria, 22--with chronic liver diseases and 30--controls were examined. European standardised method for the determination of ALAD activity blood was used. The significantly lowest activity was found in porphyric patients even after reactivation with zinc and dithiothreitol. There was no significant difference between ALAD activity in chronic liver diseases and controls. These results and lack of correlation between enzyme activity and liver function tests suggest that ALAD activity is decreased in chronic hepatic porphyria and is independent of liver damage.