Disorders of haem metabolism: iron and the porphyrias
Martin Andrew Crook in Clinical Biochemistry & Metabolic Medicine, 2013
The acute attack is marked by an increase in ALA and PBG production. In acute intermittent porphyria, this increase is due to the block imposed by an inherited deficiency of PBG deaminase; in hepatic coproporphyria and variegate porphyria, this enzyme becomes rate limiting and is unable to respond normally to the increased demand. The increase in urinary ALA and PBG concentrations is the hallmark of the acute porphyric attack and, in hereditary coproporphyria and variegate porphyria, is superimposed on all the other biochemical abnormalities. The accelerated activity of the pathway and the spontaneous conversion of the precursors to porphyrin lead to increased urinary porphyrin excretion. About 1 per cent of acute attacks are fatal. It is important to stop precipitating drugs and not to use medications that could evoke an attack. Convulsions may be treated with gabapentin or vigabatrin. Haem arginate, given by slow intravenous infusion, can result in a reduction in ALA and PBG concentrations and thus reduce some of the features of the acute attack, but not usually the neuropathy.
Autonomic Nervous System Disorders
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
Major component of autonomic failure: Diabetes.Acute inflammatory polyradiculopathy (Guillain–Barré syndrome).Acute intermittent porphyria.Primary and secondary amyloidosis.Familial dysautonomia (hereditary sensory and autonomic neuropathy).Sjögren's syndrome and, rarely, other connective tissue disorders.Chronic idiopathic sensory and autonomic neuropathy.
Unexplained Fever In Neurological Disorders
Benedict Isaac, Serge Kernbaum, Michael Burke in Unexplained Fever, 2019
For the purpose of demonstrating the role of metabolic changes in the hypothalamus and other regions of the CNS, the following case report of acute intermittent porphyria is instructive. A 21-year-old female suffered from personality changes following the use of oral contraceptives. A year later she started to take phenobarbitol and phenytoin for severe headaches and episodic vertigo and soon after she suffered severe abdominal pain, nausea, and fever. Seizures and rapid decline in alertness initiated admission. Subsequently the family history and laboratory work-up indicated acute intermittent porphyria. She sunk into coma and the fever persisted. A complete fever work-up including CSF examination was negative. In addition to encephalopathy she manifested with the syndrome of inappropriate ADH secretion, as an additional manifestation of hypothalamic damage. She also showed clinical and radiological evidence for bilateral temporal lobe function impairment (Kluver-Bucy syndrome).55
Safe usage of bicalutamide and goserelin in a male patient with acute intermittent porphyria and prostate cancer
Published in Scandinavian Journal of Urology, 2019
Frid Sofie Lichtwarck Bjugn, Elin Storjord, Roy Morten Kristensen, Ole-Lars Brekke
Acute intermittent porphyria (A.I.P.) is an autosomal dominant inherited metabolic disorder that is due to heterozygous mutations in the hydroxymethylbilane synthase enzyme of the haem biosynthesis [1]. Deficiency of the enzyme alone is not sufficient to cause attacks, since most patients with such mutations are asymptomatic [2]. Symptoms occur when exacerbating factors induce haem synthesis by increasing the activity of the rate limiting ALAS-1 enzyme, leading to accumulation of the porphyrin precursors porphobilinogen (P.B.G.) and aminolevulinic acid (A.L.A.) [1,2]. Medications are among the most important exacerbating factors and safe usage of drugs in A.I.P. patients may be a challenge [3]. The most common clinical presentation of A.I.P. is acute attacks with severe abdominal pain that may be accompanied by vomiting, fatigue, dark red urine, electrolyte disturbances and/or neuropsychiatric symptoms. Attacks are highly variable, both in severity and frequency. The secretion of A.L.A. and P.B.G. in urine is increased during attacks [4]. The northern parts of Sweden and Norway have the highest prevalence of A.I.P. in the world [2,5].
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
AIP is inherited at birth, and is difficult to diagnose in prepubescent children. A mutation in the hydroxymethylbilane synthase gene will result in loss-of-function of prophobilinogen deaminase to function. It is not guaranteed one will develop porphyria if he or she possesses this mutation, as only 10% of people who possess the mutation show symptoms of porphyria [1]. Sweden has higher occurrences with 1 in 10,000 people possessing this disease [12]. It has been observed that 89% of people with AIP have mutations in the W198X, R173W, and R167W genes, with more clinical manifestations occurring in women [1, 13]. Heterozygous missense variants within the HMBS gene may also be attributed to causing encephalopathy in AIP [14]. A single base-pair insertion (887insA) in exon 14 or a missense mutation (Arg26His) in exon 2 within the porphobilinogen deaminase (PBG-D) gene can also cause acute intermittent porphyria [15, 16].