title: The porphyrias.
abstract: The porphyrias are caused by hereditary defects in the synthesis of heme. Each porphyria is characterized by a unique enzyme defect and measurable elevations of specific heme precursors. While qualitatively normal, these precursors accumulate to cause protean signs and symptoms. Photosensitivity should raise the suspicion of a porphyria, especially in a child or a young adult. The skin, teeth and eyes may provide clues to the diagnosis in some cases.
mesh_terms: D000293:Adolescent; D000328:Adult; D000622:Aminolevulinic Acid / Q000652:urine; D001815:Bloodletting; D002338:Carotenoids / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine / Q000627:therapeutic use; D006801:Humans; D007223:Infant; D008107:Liver Diseases / Q000175:diagnosis / Q000473:pathology / Q000628:therapy / Q000652:urine; D008297:Male; D008875:Middle Aged; D011162:Porphobilinogen / Q000652:urine; D011164:Porphyrias / Q000175:diagnosis / Q000473:pathology / Q000628:therapy / Q000652:urine; D012867:Skin / Q000473:pathology; D012871:Skin Diseases / Q000175:diagnosis / Q000473:pathology / Q000628:therapy / Q000652:urine; D012872:Skin Diseases, Vesiculobullous / Q000473:pathology; D013472:Sunlight / Q000009:adverse effects; D014578:Uroporphyrins / Q000652:urine; D019207:beta Carotene
chemical_list: D014578:Uroporphyrins; D019207:beta Carotene; D002338:Carotenoids; D011162:Porphobilinogen; D002738:Chloroquine; D000622:Aminolevulinic Acid