Porphyrias (Q40109)

Porphyrias constitute a group of diseases characterised by intermittent neuro-visceral manifestations, cutaneous lesions or by the combination of both. All porphyrias are caused by a deficiency in one of the enzymes of the heme biosynthesis pathway resulting in an accumulation of porphyrins and/or their precursors in the liver or bone marrow. Clinical signs of the disease usually appear in adulthood, but some porphyrias affect children. Porphyrias can be classified according to the main location of the metabolic anomaly. Direct or indirect neurotoxicity may cause neurological manifestations. Transmission of hereditary porphyrias is autosomal and either dominant with weak penetrance or recessive with complete penetrance. Diagnosis is mainly based on the measurement of porphyrins and their precursors in biological samples.