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Diseases of the Peripheral Nerve and Mononeuropathies
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Diana Mnatsakanova, Charles K. Abrams
Three forms associated with neuropathy: Acute intermittent porphyria (AIP): porphobilinogen deaminase deficiency.Hereditary coproporphyria (HCP): defects in coproporphyrin oxidase.Variegate porphyria (VP): impaired protoporphyrinogen oxidase.
Liver Diseases
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Hereditary coproporphyria is inherited as an autosomal dominant disorder. The neurologic-visceral symptoms in some cases are similar to the acute intermittent porphyria and photosensitivity rarely occurs.76 In several instances, no clinical symptoms appear at all. However, the disease may be provoked by drugs or other chemicals which induce aminolevulinic acid synthetase in the liver.208,240 The major laboratory finding is an increased fecal coproporphyrin excretion. Additionally, urinary levels of δ-aminolevulinic acid, porphobilinogen, and coproporphyrin are elevated. In remission the only biochemical sign of the disease is increased fecal coproporphyrin. This indicates that the major deficiency lies in the activity of coproporphyrin dehydrogenase.
Sideroblastic Anemia and Porphyrias
Published in Harold R. Schumacher, William A. Rock, Sanford A. Stass, Handbook of Hematologic Pathology, 2019
Hereditary coproporphyria, a disorder caused by an enzyme defect in coproporphyrinogen oxidase, is inherited as an autosomal dominant trait. It is characterized by neurologic manifestations as in acute intermittent porphyria, or cutaneous manifestations in the form of a vesiculobullous eruption similar to that in porphyria cutanea tarda. Treatment of the acute episode involves the use of sunscreens and avoidance of sunlight.
Givosiran, a novel treatment for acute hepatic porphyrias
Published in Expert Review of Precision Medicine and Drug Development, 2021
Manish Thapar, Sean Rudnick, Herbert L. Bonkovsky
The human porphyrias generally are classified according to the principal sites of overproduction of porphyrins or porphyrin precursors as being either hepatic or erythropoietic. The hepatic porphyrias are further classified as being ‘acute’ or ‘inducible’ (due to up-regulation of ALA synthase-1) or as being ‘chronic.’ The acute designation is used for four relatively rare disorders, all due to inherited defects in normal heme synthesis [ALA dehydratase deficient porphyria (ADP); acute intermittent porphyria (AIP), due to partial deficiency of HMBS; hereditary coproporphyria (HCP), due to partial deficiency of CPOX; and variegate porphyria (VP), due to partial deficiency of PPOX]. When these are biochemically active (elevated ALA and PBG), there is induction of ALA synthase-1 in the liver, as already described, leading to marked overproduction of ALA, and usually also of porphobilinogen (PBG). The chronic hepatic porphyrias comprise two disorders, porphyria cutanea tarda (PCT) and hepatoerythropoietic porphyria (HEP), which, respectively, are due to partial (∼50%) or nearly total (>90%) deficiency of uroporphyrinogen decarboxylase (UROD), the fifth enzyme of the heme synthetic pathway. PCT, the disorder with milder UROD deficiency, occurs mainly in adult men with underlying liver disease, whereas the disorder with severe UROD deficiency is HEP. It is usually manifest in childhood or infancy and continues life-long.
Neurological and neuropsychiatric manifestations of porphyria
Published in International Journal of Neuroscience, 2019
Yiji Suh, Jason Gandhi, Omar Seyam, Wendy Jiang, Gunjan Joshi, Noel L. Smith, Sardar Ali Khan
Porphyria refers to a group of disorders that results from a defect in the heme biosynthetic pathway. Most heme in mammals is produced in erythroid cells. The central and peripheral nervous systems may be affected as well as various other organ systems. The subtypes of porphyria can be categorized as hereditary coproporphyria (HC), acute intermittent porphyria (AIP), variegate porphyria (VP) and porphyria cutanea tarda. Not all types cause neurologic problems. HC, AIP and VP are hepatic pathologies with neurologic manifestations that are inherited in an autosomal dominant pattern [1]. Porphyria cutanea tarda, which is the most common among patients, and erythropoietic protoporphyria are not neurologic, but have cutaneous manifestations [2]. A physician should suspect porphyria if the patient has motor-predominant peripheral neuropathy, gastrointestinal distress, dermatologic, and neuropsychiatricrelated complications. According to Anderson et al., porphyria occurs in about 0.5 to 10 per 100,000 people [2].
Porphyrias and photosensitivity: pathophysiology for the clinician
Published in Postgraduate Medicine, 2018
Loukas Kakoullis, Stylianos Louppides, Eleni Papachristodoulou, George Panos
Porphyrias manifest with either one or more of these clinical syndromes, depending of the substrates being accumulated. Acute intermittent porphyria (AIP) manifests as acute neurovisceral disease only, hereditary coproporphyria (HCP), and variegate porphyria (VP) combine acute neurovisceral disease with delayed blistering photosensitivity, whereas porphyria cutanea tarda (PCT) and congenital erythropoietic porphyria (CEP) manifest only as delayed blistering photosensitivity. However, it should be noted that photosensitivity in CEP is far more severe and can lead to photomutilation and disfigurement. Immediate and painful photosensitivity characterizes the two forms of protoporphyria, erythropoietic protoporphyria (EPP) and X-linked erythropoietic protoporphyria (XLEPP) [7,9,11]. Finally, an ultra-rare form of porphyria, ALA dehydratase deficiency porphyria (ALADP), manifests with acute neurovisceral disease, but due to the paucity of reported cases (less than 10 cases have been reported [7]), the complete range of its manifestations remains unknown [11], and thus will not be discussed. The main source of heme precursors in AIP, PCT, HCP, and VP is the liver, whereas the bone marrow produces the excess of porphyrins observed in CEP, EPP and XLEPP [7]. In hepatoerythropoietic porphyria, another ultra-rare form of porphyria, both the liver and bone marrow contribute to the excess production of heme precursors [12,13].