Hepatic porphyrias.

Introduction, - This review is aimed at presenting classification and diagn osis criteria of hepatic porphyrias and at proposing guidelines for diagnos is and management of these diseases. Current knowledge and key points. - Porphyrias are inherited disorders: eac h type of porphyria is the result of a specific decrease in the activity of one of the enzymes of heme biosynthesis. Porphyrias are presently classifi ed as erythropoietic or hepatic, depending on the primary organ in which ex cess production of porphyrins or precursors takes place. From 1970 to 1998, there have been important advances in the understanding of these diseases: specific enzyme deficiencies have been demonstrated, and genes have been i solated and located. These advances have been followed, rapidly by identifi cation of mutations. Perspectives and projects. - Treatment of acute attacks by hematin complete ly changed the disease prognosis. Relationships between porphyria cutanea t arda and hepatitis C virus or hemochromatosis have also been clarified Howe ver, several important issues are still not solved: for instance, pathogene sis of neuronal dysfunction that produces the acute attacks is poorly under stood. Differences related to susceptibility to develop acute attacks are n ot known. (C) 1999 Elsevier, Paris.