[The porphyrias: it's definition, classification and differential diagnosis].

The porphyrias are diseases of enzyme deficiency in the heme synthetic pathway. They are classified into eight subtypes, two of which, ALADP and HEP, have been added as new subtypes during the past 10 years. These eight subtypes are divided into two groups, hepatic and erythropoietic. Hepatic porphyrias include AIP, ALADP, VP, HCP, PCT and HEP. Erythropoietic porphyrias consist of two subtypes, CP and EPP. From the clinical point of view, these subtypes may, also, be divided into acute and cutaneous porphyrias. AIP, ALADP, VP and HCP belong to acute porphyria. CP, EPP, PCT, and HEP to cutaneous porphyria. The diagnosis of porphyrias and differential diagnosis of subtypes are made by analyzing porphyrias and it's precursors in urine, blood and feces.