The porphyrias: pathophysiology.
Porphyrias are a group of inherited and acquired metabolic disorders due to a defect in haem biosynthesis. An enzymatic defect at different steps of haem synthesis leads to tissue accumulation and excessive excretion of porphyrins and/or their toxic precursors. The specific patterns of accumulation determine the variety of clinical manifestations, ranging from acute neurovisceral attacks to skin lesions and liver disease. Most enzyme defects represent partial deficiencies, while familial cases are linked to autosomal or recessive traits. The incomplete penetrance of the genetic defects often requires the triggering or aggravating effect of host-related or environmental factors. While genetics has a role in confirming clinical suspicion and in family screening, biochemical and clinical studies are still central in the diagnosis.
Pietrangelo
Antonello
A
Division of Internal Medicine, Center for Hereditary Liver Diseases, Mario Coppo Liver Research Center, University Hospital of Modena, Via del Pozzo 71, 41100, Modena, Italy. antonello.pietrangelo@unimore.it
D003304:Coproporphyrinogen Oxidase / Q000235:genetics / Q000378:metabolism; D005294:Ferrochelatase / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006418:Heme / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D011163:Hydroxymethylbilane Synthase / Q000235:genetics / Q000378:metabolism; D000623:Porphobilinogen Synthase / Q000172:deficiency / Q000235:genetics; D011164:Porphyrias / Q000201:enzymology / Q000209:etiology* / Q000235:genetics; D050768:Protoporphyrinogen Oxidase / Q000235:genetics / Q000378:metabolism; D014575:Uroporphyrinogen Decarboxylase / Q000172:deficiency / Q000235:genetics; D014576:Uroporphyrinogen III Synthetase / Q000235:genetics / Q000378:metabolism
D006418:Heme; D003304:Coproporphyrinogen Oxidase; D050768:Protoporphyrinogen Oxidase; D011163:Hydroxymethylbilane Synthase; D014575:Uroporphyrinogen Decarboxylase; D000623:Porphobilinogen Synthase; D014576:Uroporphyrinogen III Synthetase; D005294:Ferrochelatase