Porphyrias.

Seven different porphyrias form a group of inherited metabolic disorders, each resulting from a partial deficiency of a specific enzyme in the haem biosynthesis pathway. Clinically, the three most important entities are an acute porphyric attack and acute and chronic skin symptoms. Porphyrias are rare and sometimes misdiagnosed, because various symptoms and signs mimic other diseases. Once porphyria is suspected, biochemical analyses easily detect porphyrins and their precursors from blood, urine, or faeces. Mutation screening can be done at the quiescent phase of the disease. Pathogenetic mechanisms and clinical manifestations differ in individual porphyrias and most of them require a specific treatment. Early diagnosis and information about precipitating factors can diminish mortality and prevent subsequent attacks among patients with acute porphyrias, so mutation screening is recommended for family members.