Review: molecular pathogenesis of hepatic acute porphyrias

The molecular cloning of cDNA and genes encoding enzymes of the haem biosynthetic pathway have permitted the genetic defects underlying acute intermittent porphyria (AIP) and hereditary coproporphyria to be unravelled. In AIP, many different gene abnormalities have been documented since 1989. The prevalence of specific defective alleles among AIP families depends on which human population is studied. Founder effects are likely to account for a high frequency of a single mutation in Finland and, to a lesser extent, in Holland, while many other mutations have only been found once, each of them in a single family. In hereditary coproporphyria several different mutations have already been identified since 1994, suggesting that a large allelic heterogeneity also exists. The search for mutations in variegate porphyria has just started since the recent publication of the human cDNA sequence. Direct detection of the mutations using DNA analysis brings a growing contribution to the detection of asymptomatic carriers among relatives of porphyric patients and will, therefore, improve the prevention of acute attacks.     

Treatment of urinary tract infections caused by unknown bacteria (author''s transl)

The occurrence of hepatic porphyrias--acute intermittent porphyria (AIP) and variegate porphyria (VP)--in Finland has been studied. During a period of 9 years 107 patients with AIP and 45 patients with VP were found. The prevalence of hereditary hepatic porphyrias was calculated to be 3.4 per 100 000 inhabitants. The patients belonged to 42 different families. Eighty-nine patients (59%) had had acute attacks, whereas 63 were symptomless latent cases. Precipitating factors, symptoms and excretion of porphyrins and their precursors did not significantly differ from what has been reported earlier from other parts of the world. A slight fragility of the skin on the back of the hands was noted in some 50% of VP patients. Abnormal sensitivity to sunlight could not be seen in a single case. However, about 50% of patients with VP showed an abnormal reaction when irradiated with artificial ultraviolet light. The difference in the skin symptoms in South African and Finnish VP patients is discussed.     

The porphyrias: a brief overview based on 25 years of experience (1969-1994) by the Department of Dermatology of the Hospital Clinic and Faculty of Medicine of Barcelona, Spain

The porphyrias are uncommon diseases caused by enzymatic deficiencies in the heme pathway. In the 25 year period 1969-1994, the Department of Dermatology of the Hospital Clinic of Barcelona has been able to study 793 cases of porphyria (724 cases of PCT, 27 of EPP, 26 of PV, 5 of CEP, 5 of HEP, 5 of AIP, 1 of HCP). Homozygous expression of an enzymatic deficiency in the heme pathway produces severe disease. Commonly, clinical manifestations appear in the homozygous state (the autosomal recessive porphyrias). However, homozygous forms of autosomal dominant porphyrias may occur exceptionally. Moreover, there are cutaneous porphyrias whose clinical manifestations do not permit dermatologists to classify them clearly into one of the well-defined syndromes. These uncommon and atypical forms are difficult to recognize without biochemical and enzyme studies. The porphyrias have a wide clinico-biochemical spectrum, including a large proportion of well defined diseases. Nevertheless, atypical forms occur and may be difficult to evaluate. It is important to note the genetic heterogeneicity of porphyrias, which accounts for the varying phenotypic expression.     

Autonomic regulation of the cardiovascular system in patients with chronic cholecystitis and hepatitis

Three hepatic porphyrias--acute intermittent porphyria, hereditary coproporphyria and variegate porphyria--are characterized by episodic acute attacks that consist of various neuro-psychiatric symptoms and signs, such as abdominal pain, vomiting, constipation, hypertension and tachycardia associated with increased excretion of porphyrins and porphyrin precursors. Peripheral neuropathy is manifested as pain in the extremities, and it may progress to a severe motor neuropathy. Measurement of porphobilinogen in the urine gives a prompt diagnosis during acute attacks. Attacks are often induced by precipitating factors such as drugs, alcohol, infection, fasting or changes in sex-hormone balance, and they should be eliminated when a patient is treated during an attack. Heme, the end biosynthetic product, is the most effective therapy for restoration of porphyrin biosynthesis to normal, and it is usually infused at 3 mg/kg daily for 4 days. Adequate calories are necessary and parenteral nutrition with carbohydrates may be necessary. Attacks may also require therapy for hypertension, pain and epileptic seizures. Strict avoidance of all precipitating factors may not be necessary in the asymptomatic phase.     

Treatment of photodermatoses with carotinoids (author's transl)

39 patients were treated with carotinoids (beta-carotene alone or combined with canthaxanthine) with an oral dose of 50-150 mg/d, some of them for a period of several years. 23 of these were patients with porphyria (erythropoietic protoporphyria [EPP] 20, congenital erythropoietic porphyria 2, erythropoietic coproporphyria 1); 16 patients were suffering from various photodermatoses (solar urticaria 6, actinic reticuloid 5, UV-A intolerance 1, unclassified photodermatoses 4). Tolerance of the carotinoids was very good; no side effects were seen except for a yellow discoloration of the skin. In 19 of 20 EPP patients the result of the treatment was good, whereas no improvement was seen in the other kinds of porphyria. Of the 16 cases of photodermatoses not caused by porphyrinopathy, 6 responded to the therapy (solar urticaria 2, actinic reticuloid 2, UV-A intolerance 1, unclassified photodermatosis 1). Some cases showed great improvement as a result of the treatment.     

Mortality in patients with acute intermittent porphyria requiring hospitalization: a United States case series

Acute intermittent porphyria (AIP) is a genetic disorder in which patients may have life threatening attacks of neurologic dysfunction. This study examined the prognosis during the past 50 years of patients in the United States who required hospitalization for porphyric attacks. The cumulative survival was determined for 136 patients with AIP who were hospitalized for porphyric attacks between 1940 and 1988. Diagnosis was established on the basis of clinical symptoms, in combination with increased urinary excretion of porphobilinogen. The patient group had an average age of 32 years (range 9 to 75) at diagnosis and consisted of 43 males and 93 females. At follow-up, 19 males (44%) and 31 females (33%) were decreased. The standardized mortality ratio for the 136 patients, compared to an age-matched hypothetical population experiencing USA 1970 Census Death Rates was 3.2, with a 95% confidence interval of 2.4-4.0. Most deaths occurred during the initial porphyric attack (20% of deaths) or a subsequent attack (38% of deaths). Suicide was also common (five deaths). Comparison was made between 50 patients who were diagnosed before 1971, the year in which hematin therapy became available, and 86 patients who were diagnosed afterward. There was improved survival in the latter group, particularly after 10 years from the time of diagnosis, but this did not reach statistical significance. In conclusion, the proportionate increase in mortality due to symptomatic AIP was three-fold compared to the general population during the past 50 years. The major cause of the increased mortality was the porphyric attack itself.     

Reduction of porphyrin excretion in porphyria variegata by propranolol. A case report

DL-Propranolol was shown to reduce the elevated urinary excretion of porphyrins and their precursors in a patient with variegate porphyria and to improve the patient's symptoms during attacks of the disease.     

Germline mutations in the MEN1 gene: basis for predictive genetic screening and clinical management of multiple endocrine neoplasia type 1 (MEN1) families

BACKGROUND AND OBJECTIVE: Mutations in the MEN 1 gene were recently discovered as the causative genetic defect of the autosomal dominantly inherited multiple endocrine neoplasia type 1. It was the aim of this study to evaluate the spectrum of MEN 1 mutations in our own series of patients in order to obtain a basis for predictive family screening. PATIENTS AND METHODS: Genomic DNA from peripheral blood of 21 patients with MEN 1, members of 14 non-related MEN 1 families, was examined for MEN 1 germ-line mutations by means of single-strand conformation variant analysis (SSCP) and direct DNA sequencing. In addition, blood from 20 asymptomatic family members of five families was tested for its predictive value. RESULTS: Eleven different heterozygotic germ-line mutations, among them eight frameshift, two missense and one nonsense mutations, were identified. In four of the 20 asymptomatic members from five MEN 1 families who had been tested after appropriate genetic counselling, the MEN 1 mutation characteristic for the particular family was found. Clinical screening programme in three mutation carriers revealed abnormal findings in all three: one primary hyperparathyroidism, one prolactinoma and one nonfunctioning pancreatic tumour each. The 16 family members without MEN 1 mutation were spared further unnecessary screening investigations. CONCLUSION: Although the function of the MEN 1 gene is not yet known, molecular genetic tests provide a basis for genetic counselling, predictive genetic screening and clinical management of MEN 1 families.     

Neuropathy in erythropoietic protoporphyrias

Peripheral neuropathy (PN) has rarely been described as a complication of erythropoietic protoporphyria (EPP). We describe three episodes of PN and the electrophysiologic findings in two patients with EPP. PN is seen in patients with EPP and hepatic failure and raised free erythrocyte protoporphyrin or serum protoporphyrin levels and is identical to that seen in acute intermittent porphyria. Recognition is important because of the good eventual prognosis.     

Screening of certain anaesthetic agents for their ability to elicit acute porphyric phases in susceptible patients

The activity of delta-aminolaevulinic acid synthetase (E.C. 2.3.1.37) (ALA-S) was measured in rat liver after the simultaneous administration of various anesthetic agents and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) in vivo. Flunitrazepam, Althesin and phenobarbitone caused a significant increase in the activity of the enzyme which was not observed with propanidid, etomidate and minaxolone. It is suggested that DDC-treated rat, which resembles latent human variegate porphyria, may be a more valid method of testing drugs for their ability to elicit acute porphyric phases in susceptible individuals. The anaesthetic agents which induced the activity of hepatic ALA-S in this model are not recommended in patients with genetic hepatic porphyria.     

Treatment of the porphyrias

There are seven porphyrias which are caused by defective functions of the enzymes in the haem biosynthesis. The clinical classification of porphyrias are divided into three types which are neuroporphyria, neurocutaneous porphyria and cutaneous porphyria. For acute porphyric attack of neuroporphyria and neurocutaneous porphyria, the treatments of choice are administration of glucose and/or hematin, haem arginate and tinprotoporphyrin. Porphyria cutanea tarda in cutaneous porphyria is controlled by removal of iron by phrebotomies or low-dose chloriquine. A novel approach of intravenous administration of interferon may be useful to control the associated case of chronic hepatitis type C. Skin symptoms in erythropoietic protoporphyria can be alleviated with beta carotene. Hepatic failure due to protoporphyria may need a liver transplantation. Cimetidine, a H2-receptor antagonist, may be useful in the treatment of acute porphyric attack and in remission stage in neuroporphyrias, neurocutaneous porphyrias and cutaneous porphyrias such as porphyria cutanea tarda and protoporphyria.     

Acute intermittent porphyria with relapsing acute pancreatitis and unconjugated hyperbilirubinemia without overt hemolysis

A 36-year-old woman was admitted to hospital with a first attack of acute intermittent porphyria. At the same time increased serum levels of amylase and lipase as well as an increased amylase clearance to creatinine clearance ratio were observed, permitting the diagnosis of acute pancreatitis. The etiology of the latter could not be determined. In addition, elevation of indirect bilirubin without evidence of hemolysis was observed Gilbert's syndrome was suspected. 40 weeks after the first episode, a second attack of identical abdominal pain was noted, with elevation of pancreatic enzymes in the serum. There is evidence that acute intermittent porphyria and acute relapsing pancreatitis may have some etiological connection in this patient.     

Defining the practice population in fee-for-service practice

OBJECTIVE: To develop and validate a technique for defining a practice population of discrete individuals based on multiyear family practice fee-for-service billings data. DATA SOURCES/STUDY SETTING: Nineteen family physicians in Ontario, Canada who converted from fee-for-service to capitation payment. Data sources were fee-for-service billings data for the three-year period prior to the conversion from fee-for-service to capitation payment and the rosters of enrolled patients for the first and third years after the change to capitation payment. STUDY DESIGN: The billings-based definition of the physician's practice population was compared against the Year 1 roster. We also compared the billings-based practice population and the Year 1 roster to the physician's Year 3 roster to identify patients who might have been missed during the roster development process. Our principal analyses were an assessment of the sensitivity of the billings-based definition of the practice population (EPP), the positive predictive value of EPP, and the agreement between EPP and the rostered patient population (RPP). We also examined the ratio between EPP and RPP to determine EPP's accuracy in estimating the practice denominator. DATA COLLECTION/EXTRACTION METHODS: The practice population for each physician at the time of conversion from fee-for-service to capitation payment was defined as (a) all persons for whom the physician billed the provincial health insurance plan for at least one visit during the year immediately prior to joining the capitation-funded program; and (b) all additional patients for whom the physician billed the plan for at least one service in each of the two preceding years. Data extraction was carried out within the Ministry of Health in order to preserve the anonymity of patients and physicians. Data were provided to the investigators stripped of patient and physician identifiers. PRINCIPAL FINDINGS: The mean sensitivity and positive predictive value of EPP were 95.3 percent and 87.4 percent, respectively. The level of agreement between EPP and RPP averaged 84.4 percent. The mean ratio of EPP to RPP was 1.21 (95 percent C.I. 1.030-1.213). Correction for roster false-negatives increased the sensitivity, positive predictive value, and agreement between EPP and the practice population, and reduced the mean ratio of EPP to the practice population to 1.068 (95 percent C.I. 1.010-1.127). CONCLUSIONS: The practice population can usefully be defined in fee-for-service family practice on the basis of multiyear fee-for-service billings data. Further research examining alternative encounter-based practice population definitions would be valuable.     

Nutritional screening for the elderly: a CNS role

We report a cytogenetic and fluorescence in situ hybridization study of a family in which a female child showed all the main characteristics of Angelman syndrome. Her karyotype revealed a translocation between chromosomes 5 and 15 with a partial deletion from 15pter to the Angelman region. Several members of her family appeared to be carriers of the same translocation, but showed no symptoms. The karyotypes showed a marker chromosome, that was not present in the female with Angelman syndrome. Fluorescence in situ hybridization revealed that the marker chromosome corresponded to material from chromosome 15. The present study is in agreement with the suggestion that genomic imprinting is one of the mechanisms involved in Angelman syndrome.     

Flavonoids in the leaves of Digitalis lanata (Ehrhart) 1. Communication) (author''s transl)

The course of acute intermittent porphyria is described in a patient who died during an acute exacerbation of the disease. An analysis of the urinary porphyrin precursors (delta-aminolaevulinic acid and porphobilinogen), the determination of toal porphyrin excretion and the separation of haem precursors in the urine according to the number of carboxylic groups demonstrate different degrees of biochemical severity in the individual consanuinious members of this patient's family. The detection of latent carriers is of particular importance since the avoidance of porphyrogenic substances is the most important prophylactic measure to be undertaken in all latent clinical cases. According to our experience, however, prophylactic measures must also be extended to young consanguineous family members with negative excretion patterns in view of the difference in age at which the disease manifests itself.     

Rapid molecular diagnosis of erythropoietic protoporphyria among Swiss patients

Erythropoietic protoporphyria (EPP) is an autosomal dominant inherited disorder with incomplete penetrance. It is caused by partial deficiency of ferrochelatase, the last enzyme in the heme biosynthetic pathway. Measurement of protoporphyrin concentrations in red cells and feces, although sufficient for diagnosis of symptomatic EPP patients, fails to detect asymptomatic gene carriers. We have developed a molecular diagnostic procedure for rapid and reliable screening of five known mutations in the ferrochelatase gene among Swiss EPP patients in a single denaturing gradient gel electrophoresis (DGGE) gel.     

Elevated serum and CSF levels of soluble CD30 during clinical remission in multiple sclerosis

OBJECTIVE: To ascertain the presence of the Th2 response in MS patients by evaluating the level of soluble (s) CD30 across the clinical spectrum of MS and during relapse and remission. BACKGROUND: MS is considered a T-cell-mediated disorder with the immune attack dominated by a Thl cytokine response. Elevated levels of sCD30 have been associated with CD4+ cells that secrete Th2-type cytokines. METHODS: Levels of sCD30 were determined in the serum and CSF of patients with primary progressive MS, secondary progressive MS, relapsing-remitting MS (RRMS), both in relapse and remission, and in patients with other inflammatory neurologic disease (IND) and noninflammatory neurologic disease (NIND). None of the patients were on immunomodulatory treatment. RESULTS: Higher serum levels of sCD30 were detected in all MS subgroups and IND patients compared with NIND patients. RRMS patients in remission had significantly higher levels than those in relapse (median, 45.7 U/mL versus 18.3 U/mL; p = 0.04). Significantly higher CSF levels were also found in all groups, except those with RRMS in relapse compared with NIND patients. Again, RRMS patients in remission had higher CSF sCD30 levels compared with those in relapse (median, 4.0 U/mL versus 3.0 U/mL; p = 0.08). CONCLUSIONS: Serum and CSF levels of sCD30 are increased in MS, particularly during remission. The results provide additional evidence for the presence of a Th2 response and indicate that sCD30 may be of value as a marker of lesion resolution.     

Factors influencing the fluorescence spectra of the formaldehyde-induced reaction product of 5-hydroxytryptamine

Fluorescence excitation and emission spectra of the formaldehyde-induced fluorophore of 5-hydroxytryptamine in a Sephadex model have been examined following exposure to hydrochloric acid or ammonia vapour. Exposure to hydrochloric acid vapour produced excitation spectra with broad maxima centred around 400 nm, whilst exposure to ammonia vapour intensified the maximum normally seen at approximately 450 nm relative to that seen at 400 nm. The emission maximum was generally broad and poorly defined following exposure to hydrochloric acid vapour; exposure to ammonia vapour had little effect on its location. Exposure of the formaldehyde-induced fluorophore in models containing 5-hydroxytryptamine to 300 nm irradiation caused a substantial shift in the position of the emission maximum; a concomitant increase in the fluorescence intensity was also observed. When the fluorescence present in duodenal enterochromaffin cells was examined after similar treatment, a number of differences in the response of the fluorophore were noted.     

Ferrochelatase activities in patients with erythropoietic protoporphyria and their families

Ferrochelatase, estimated as zinc chelatase, was measured in the lymphocytes of 30 patients with erythropoietic protoporphyria (EPP), in 35 first- or second-degree relatives of patients with EPP, and in 50 healthy controls. In 30 EPP patients the zinc chelatase level (mean +/- standard deviation, SD) was 0.45 +/- 0.10 nmol of zinc protoporphyrin per hour per milligram of protein, in 14 EPP carriers the zinc chelatase level (mean +/- SD) was 0.42 +/- 0.09 and in 50 healthy controls the zinc chelatase level (mean +/- SD) was 0.84 +/- 0.27. All patients with EPP were also demonstrated to have an elevated protoporphyrin level in their red blood cells: the erythrocyte protoporphyrin levels were as follows EPP patients (mean +/- SD) 1300 +/- 758 nmol protoporphyrin/dl, EPP carriers (mean +/- SD) 60 +/- 24, and healthy controls (mean +/- SD) 50 +/- 25 (P < 0.001 for EPP patients compared to controls and EPP carriers). The families of 12 out of 15 EPP patients were examined with respect to the mode of inheritance of the disorder. Of 35 relatives, 14 were carriers of EPP, as characterized by reduced zinc chelatase activity in lymphocytes and by a normal protoporphyrin level in red blood cells. None of the 14 EPP carriers had presented with clinical symptoms of EPP. The mod of inheritance was autosomal dominant in seven of the 12 examined families, and autosomal recessive in two. In two families only one parent could be investigated, but we nevertheless concluded that the inheritance was autosomal dominant. Inheritance in one EPP family could not be elucidated as both parents showed normal zinc chelatase levels and did not demonstrate abnormal erythrocyte protoporphyrin levels.