Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “porphyria”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1978

Tryptophan pyrrolase, the regulatory free haem and hepatic porphyrias. Early depletion of haem by clinical and experimental exacerbators of porphyria.

1. The importance of the early depletion of liver haem in the production of porphyria is discussed and further supporting evidence is presented from experiments with tryptophan pyrrolase, under conditions of exacerbation of experimental porphyria by therapeutic and other agents. 2. In addition to the early depletion of pyrrolase haem by porphyrogens, a further depletion is produced when rats are given a porphyrogen plus an analogue or one of 19 drugs known to exacerbate the human disease. 3. Non-exacerbators of human porphyrias do not cause a further early depletion of pyrrolase haem and it is suggested that this system may be used as a screening test for possible exacerbation of the disease by new and existing drugs. 4. A similar further early depletion of haem is produced by combined administration of lead acetate plus phenobarbitone, thus suggesting that the depletion is a more general phenomenon in experimental porphyria. 5. The relationship between tryptophan pyrrolase and the regulatory free haem is discussed. It is suggested that pyrrolase may play an important role in the regulation of haem biosynthesis.

Animals↗
PubMed1978

Studies in porphyria. VII. Induction of uroporphyrinogen-I synthase and expression of the gene defect of acute intermittent porphyria in mitogen-stimulated human lymphocytes.

A 50% reduction in the activity of uroporphyrinogen-I (URO) synthase in liver, erythrocytes, and cultured skin fibroblasts characterizes all patients with clinically active acute intermittent porphyria (AIP). The same enzyme defect has also been demonstrated in the erythrocytes and skin fibroblasts of completely latent gene carriers of this disorder and presumably exists in the liver as well. In this study, we examined whether or not the formation of URO-synthase is impaired in AIP cells using lymphocytes treated with mitogens or infected with Epstein-Barr virus. Both mitogens (phytohemagglutinin and pokeweed mitogen) and Epstein-Barr virus induced the synthesis of URO-synthase in lymphocytes, but the induction of URO-synthase in AIP lymphocytes was only 50% as compared with that in normal lymphocytes. The impaired induction of URO-synthase in AIP lymphocytes reflects a specific gene defect because AIP lymphocytes showed normal [(3)H] thymidine uptake into DNA, [(3)H] uridine uptake into RNA, and normal delta-aminolevulinic acid (ALA) synthase, ALA-dehydratase, catalase activities, and heme content. Utilizing the same methodology, the ferrochelatase deficiency of hereditary erythropoietic protoporphyria could also be identified. The K(m) of the induced URO-synthase in AIP cells was identical to that of the enzyme in normal cells. The induced URO-synthase of mitogen-treated AIP lymphocytes was not accompanied by a concurrent enhanced level of ALA-synthase. Moreover, the URO-synthase deficiency in lymphocytes from actively ill AIP patients was not different from the level of enzyme activity when they were in clinical remission, or when compared with the enzyme activity of cells from completely latent AIP gene carriers. The results of this study indicate that the URO-synthase deficiency in AIP may be the result of a gene mutation regulating the rate of synthesis of a normal enzyme rather than a mutation causing a structural abnormality of this enzyme protein.

Acute Disease↗
PubMed1979

The porphyrias.

The heterogeneous group of diseases called the porphyrias may all be characterised by derangement of specific stages in the haem biosynthetic pathway. In the acute porphyrias; acute intermittent porphyria, urophorphyrinogen 1 synthase, hereditary coproporphyria, coproporphyrinogen oxidase and variegate porphyria, ferrochelatase or protoporphyrinogen oxidase, are the enzymes affected, whilst in the non acute porphyrias, cutaneous hepatic porphyria, uroporphyrinogen decarboxylase, congenital porphyria, uroporphyrinogen cosynthase; and erythropoietic protoporphyria; ferrochelatase are the enzymes affected. In each of the porphyrias, the activity of the initial and rate controlling enzyme of the pathway, delta-aminolaevulinic acid synthase is raised which constitutes the principal control point of the pathway. Secondary control in each of these diseases lies at the leve of uroporphyrinogen 1 synthase. As a consequence of this secondary control, there is excessive excretion of the porphyrin precursors delta-aminolaevulinic acid and porphobilinogen in the acute porphyrias and excessive excretion of porphyrins leading to solar photosensitivity in the non-acute porphyrias and in variegate and hereditary coproporphyria. There are a number of secondary metabolic aspects in the porphyrias, such as the role of steroid metabolism; the influence of drugs in the potentiation of attacks; and the potential for the pathway to branch at stages prior to porphyrin formation which result in the synthesis of various monopyrroles. The therapy of the two groups of porphyrias are quite different. Prophylaxis is important in both types but is particularly important in the avoidance of various drugs in the acute porphyrias. The acute attack may be specifically treated with carbohydrates, beta-blockers and haematin. Cutaneous hepatic porphyria may be treated by venesection, erythropoietic protoporphyria with beta caratene whilst congenital porphyria may be improved by splenectomy and chloroquine therapy.

5-Aminolevulinate Synthetase↗
PubMed2025

Porphyrias: Pathophysiology and clinical management recommendations for hepatologists.

In humans, an enzyme dysfunction in heme biosynthesis results in a heterogenous group of diseases collectively known as porphyrias. From a clinical standpoint, porphyrias can be classified as erythropoietic (congenital erythropoietic porphyria-CEP, erythropoietic/X-linked protoporphyria-EPP/XLP) or hepatic (acute hepatic porphyrias-AHPs, porphyria cutanea tarda-PCT), according to the site of organ dysfunction deemed to be responsible for the disease. In terms of total heme production, the liver accounts for the second major heme-synthesizing organ, after the bone marrow. In fact, heme is necessary as a prosthetic group in countless biologic functions, to which hepatic contribution is essential. Furthermore, the pathway of heme biosynthesis is inscribed into a network of fundamental metabolic reactions largely occurring in hepatocytes. Independent of their classification, all porphyrias share some degree of involvement of the liver, either in the pathogenesis, clinical manifestations, or as a preferential target of damage. Crucially, even those types of porphyrias that have been classically defined as erythropoietic do present a hepatic involvement, which can lead to poor clinical outcomes if neglected. Therefore, hepatologists should consider porphyrias as a differential diagnosis for otherwise unexplained presentations of liver disease. At the same time, a multidisciplinary team dealing with the diagnostic workup and clinical management of all types of porphyrias must include an expert in liver diseases. In this review, we aimed to recapitulate the main aspects of liver involvement in porphyrias, while also providing practical tools to recognize and manage these conditions from the hepatologist's perspective.

Humans↗
PubMed1977

Hepatic porphyrias. Current concepts.

Acute intermittent porphyria, variegate porphyria, and hereditary coproporphyria are hepatic porphyrias due to enzyme defects that are inherited as autosomal dominants. Porphyria cutanea tarda is considered an acquired disorder. Similar drugs or circumstances are precipitants of acute attacks in all three inherited hepatic porphyrias. The respective biochemical abnormalities are identifiable by simple, readily available laboratory tests. Management of patients with any of the inherited hepatic porphyrias is directed primarily toward prevention of attacks through avoidance of precipitants and through a diet high in carbohydrate. Therapy for porphyria cutanea tarda includes interdiction of alcohol use and repeated phlebotomy.

5-Aminolevulinate Synthetase↗
PubMed1978

[Uroporphyrinogen synthase in erythrocytes in acute intermittent porphyria: new pathobiochemical aspects (author's transl)].

Uroporphyrinogen synthase (EC 4.3.1.8) was determined in the erythrocytes of 380 patients, of which 21 showed clinical symptoms of acute intermittent porphyria. The normal range of a random sample was 61 +/- 23 mumol/1.h(x +/- 2s, n=302), including the activity of uroporphyrinogen cosynthase and the subsequent enzymes; when all the latter enzymes were destroyed by heating the haemolysate, the normal range for uroporphyrinogen synthase was 65 +/- 25 mumol/1.h(x +/- 2s, n=274). The respective activity of uroporphyrinogen synthase in patients with acute intermittent porphyria was 35 +/- 12, and 40 +/- 18 mumol/1.h which was significantly lower (p less than 0.001) than the control values. In the 21 cases of acute intermittent porphyria, the diagnosis had already been made from the presence of porphyrin precursors and porphyrin in the urine. In 7 of the 21 cases of acute intermittent porphyria, and in 6 relatives of the patients, the activity of the uroporphyrinogen synthase was in the overlap zone (40-50 mumol/1.h). 32 relatives of 9 of the patients with acute intermittent porphyria were investigated: 22 showed a significant decrease of uroporphyrinogen synthase, and 7 of these showed pathological urinary porphyrin precursors and porphyrin. The relative activity of uroporphyrinogen synthase in patients with acute intermittent porphyria was 57%. A decrease of the uroporphyrinogen synthase activity of greater than 30% compared with the mean of the controls is a sure indicator for the presence of a primary enzymic defect in the gene carrier for acute intermittent porphyria.

Acute Disease↗
PubMed1978

Variegate porphyria.

In temperate and cold climates the most usual presenting symptom of variegate porphyria is an acute porphyric attack, indistinguishable from that seen in acute intermittent porphyria. Increased fragility of the skin in sun-exposed areas occurs in only half of such patients, and even then is usually mild and easily overlooked. The diagnosis depends on fecal excretion of porphyrins, which is greatly increased in variegate porphyria and consists predominantly of protoporphyrin. Urinary excretion of porphobilinogen and delta-aminolevulinic acid increases only during acute attacks. There are reasons for thinking that variegate porphyria is commoner than hitherto supposed. During an acute attack a patient without skin symptoms may well be misdiagnosed as having acute intermittent porphyria, because of identical symptoms and excretion of porphobilinogen in the urine. Thus, for a correct diagnosis, every patient presenting with symptoms of acute porphyria requires a fecal analysis.

Acute Disease↗
PubMed1979

Porphyria cutanea tarda associated with lymphoma.

Three patients with porphyria cutanea tarda and lymphoma were seen at the Mayo Clinic. In one patient, the signs and symptoms of porphyria cutanea tarda and lymphoma occurred simultaneously, whereas in the other two, the porphyria was seen before the lymphoma occurred, three years before in one and one and a half years before in the other. Involvement of liver or marrow was not related to the development of porphyria cutanea tarda in any of the 3 patients. The porphyria cutanea tarda was not eased by radiotherapy or chemotherapy of the lymphoma, although it was probably less symptomatic after the patients were treated. While a relationship between porphyria cutanea tarda and lymphoma is speculative, confirmation will require a closer scrutiny of patients with these two diseases.

Aged↗
PubMed1979

New type of hepatic porphyria with porphobilinogen synthase defect and intermittent acute clinical manifestation.

In two young patients with acute hepatic porphyria syndrome and persisting paralyses, which increased in intensity during intermittent occurring crisis, the activity of erythrocyte porphobilinogen synthase (delta-aminolevulinic acid dehydratase) was found to be considerably diminished, below 1% of the value of normal control persons. In contrast, the activity of uroporphyrinogen synthase was normal. Both patients have been excreting high quantities of delta-aminolevulinic acid and porphyrins in urine for years. Lead intoxication has definitively been excluded. Since the relatives also show lower activities in porphobilinogen synthase, the disease of these two patients is probably a new enzymatic type of inherited acute hepatic porphyria, the excretion profile of which is qualitatively completely different from those of the known acute porphyrias. The discovery of this porphyria confirms the theory of overlapping transition in the biochemical and clinical symptoms and analogies among acute hepatic porphyrias.

Acute Disease↗
PubMed1978

[The hepatic porphyrias].

Among the different types of hepatic porphyrias, acute intermittent porphyria (AIP) and the group of chronic hepatic porphyrias (CHP) are most frequently seen in Europe. Both diseases are supposed to be inherited, but clinical manifestation mostly occurs following endogenous and especially exogenous stimulation. While recurrent attacks of abdominal and neuropsychiatric symptoms in AIP are frequently precipitated by therapeutic doses of commonly used drugs, the gradual development of porphyria cutanea tarda (PCT) from a clinically non-apparent type of CHP seems to be most commonly due to excessive and prolonged intake of alcohol. The characteristic and with regard to the laboratory findings important pathobiochemical features, the clinical symptoms, and the present therapeutic concepts of both disorders of hepatic porphyrin metabolism are discussed. The prognosis of hepatic porphyrias will be determined above all by early diagnosis of the metabolic disorder as well as by a profound medical information of the patient to avoid strictly all well-known exogenous factors which may initiate or exacerbate the disease.

Adult↗
PubMed1978

Porphyria cutanea tarda in three generations of a single family.

We examined conjugal and blood relatives of one kindred for evidence of porphyria cutanea tarda. The disease was identified in eight family members in three generations. Four were classified as having overt porphyria cutanea tarda because of four criteria: photo-enhanced dermatosis; excessive urinary excretion of uroporphyrins; characteristic thin-layer chromatographic pattern of urinary porphyrins; and decreased activity of erythrocyte uroporphyrinogen decarboxylase. Two patients with excessive excretion of uroporphyrins or characteristic chromatograms, or both, and decreased uroporphyrinogen decarboxylase activity were classified as having subclinical porphyria cutanea tarda, and two with decreased uroporphyrinogen decarboxylase activity only were classified as having latent porphyria cutanea tarda. This study provides further evidence that prophyria cutanea tarda can be a familial disease inherited in an autosomal dominant fashion. We propose a reclassification of porphria cutanea tarda as an overt, subclinical or latent disorder.

Adult↗
PubMed1977

Postulated deficiency of hepatic heme and repair by hematin infusions in the "inducible" hepatic porphyrias.

There is compelling, indirect evidence of hepatic heme deficiency due primarily to the respective genetic errors of the three inducible hepatic porphyrias, acute intermittent porphyria, porphyria variegata, and hereditary coproporphyria. The induction is enhanced by exogenous inducers such as barbiturate, estrogens and other "porphyrogenic" chemicals and factors, including glucose deprivation. The newer knowledge of the induction of delta-aminolevulinic acid synthetase [delta-aminolevulinate synthase; succinyl--CoA:glycine C-succinyltransferase (decarboxylating), EC 2.3.1.37] in relation to inadequate heme, and repression by heme, stimulated early trials of hematin infusions to overcome the acute relapse in the foregoing inducible porphyrias. Recently this experience has been considerably expanded, 143 infusions of hematin having been given in 22 cases. Studies of the effect on the serum concentrations of delta-aminolevulinic acid and porphobilinogen have shown a highly significant decline, often to 0, especially of delta-aminolevulinic acid. A distinct relationship to the clinical severity of the attack has been evident in the frequency and magnitude of decline of serum delta-aminolevulinic acid and porphobilinogen. This was regularly associated with objective clinical improvement.

5-Aminolevulinate Synthetase↗
PubMed1977

delta-Aminolevulinic acid: influences on synaptic GABA receptor binding may explain CNS symptoms of porphyria.

Symptoms of acute porphyria have been attributed to effects of delta-aminolevulinic acid (ALA). We report that ALA selectively competes for the binding of tritiated gamma-aminobutyric acid ([3H]GABA) associated with synaptic GABA receptors in central nervous system membranes. Concentrations of ALA that inhibit GABA receptor binding are consistent with levels of ALA thought to exist in the central nervous system of porphyric patients. Some of the symptoms of acute porphyria resemble those elicited by muscimol, a potent GABA agonist drug. Barbiturates, which exacerbate porphyric symptoms, are potent facilitators of the synaptic actions of GABA. The results suggest that some symptoms of acute porphyria might be attributable to a mimicking by ALA of GABA at its central nervous system receptor sites.

Aminolevulinic Acid↗
PubMed1979

Increased sensitivity to lead -- animal model: feline porphyria.

Individuals with the genetically inherited condition of latent porphyria have been previously hypothesized (1) as being a potential high risk group to elevated lead exposure. More specifically, persons with either clinical symptoms of porphyria or the latent form who also are exposed to excessive lead may have their clinical symptoms exacerbated or possibly induced prematurely, respectively. This paper presents evidence that an animal model (i.e., domestic cats with congenital porphyria) may facilitate the testing of the previous hypothesis.

Animals↗
PubMed1978

Decreased activity of hepatic uroporphyrinogen decarboxylase in sporadic porphyria cutanea tarda.

To investigate the role of uroporphyrinogen decarboxylase in the pathogenesis of the sporadic form of porphyria cutanea tarda, we measured this enzyme in liver, erythrocytes and cultured skin fibroblasts, and also measured coproporphyrinogen oxidase and the total iron concentration in liver. The mean uroporphyrinogen decarboxylase activity was lower in liver from seven male patients (9.0 pmol of coproporphyrin per minute per milligram of protein) than in 12 controls, including seven with alcoholic liver disease (22.3 pmol per minute per milligram; P less than 0.05). Coproporphyrinogen oxidase activities were the same in each group. Liver iron concentrations were lower during remission, but uroporphyrinogen decarboxylase activities were not related to clinical activity for uroporphyrin excretion. Erythrocyte and fibroblast enzyme activities were the same as in normal subjects. A hepatic uroporphyrinogen decarboxylase defect is a prerequisite for the development of porphyria cutanea tarda, but other factors, which probably do not alter uroporphyrinogen decarboxylase activity, determine the clinical onset. In sporadic porphyria cutaneous tarda, the enzyme defect appears to be restricted to the liver.

Adult↗
PubMed1977

Inheritance of porphyria cutanea tarda. Analysis of 14 cases in 5 families.

The existence of hereditary porphyria cutanea tarda must be supported by chemical and clinical investigations capable of discriminating this porphyria from porphyria variegata, because the clinical symptoms may overlap. On the basis of such investigations (normal urinary excretion of deltaALA and of porphobilinogen; urinary excretion of large amounts of 8- and 7-carboxyl porphyrins; faecal coproporphyrin and X porphyrin fractions may be increased) we have been able to classify 14 cases, out of 200 cases of PCT that we have observed in the last 7 years, as hereditary PCT. The 14 patients belong to 5 different families: two members in each of the first three families, 3 members in the fourth, and 5 members in the fifth. In this last family heredity is bilateral.

Adult↗
PubMed1975

Neuropathy in latent hereditary hepatic porphyria.

Peripheral nerve conduction velocoties were measured in 20 patients with acute intermittent porphyria and five with variegate porphyria and in 25 controls matched for age and sex. None of the porphyric patients had acute symptoms on examination, and nine had never had symptoms. Compared with the controls, patients had a significantly slower conduction velocity of the slower motor fibres of the ulnar nerve (P less than 0-001) and a slower sensory conduction velocity of the ulnar and median nerves (P less than 0-05). There was no significant difference between the patients and controls in the maximum motor conductionvelocity of the median, ulnar, deep peroneal, or posterior tibial nerves. Slight peripheral neuropathy seems to be associated with latent hereditary hepatic porphyria, even in patients who have never had symptoms.

Adolescent↗