Raili Kauppinen

Prognosis of Acute Prophyria: Occurrence of Acute Attacks, Precipitating Factors, and Associated Diseases

We evaluated the prognosis of acute porphyria among 206 adult Finnish patients with acute intermittent porphyria (AIP) or variegate porphyria (VP). The series represents all known patients with these porphyrias in Finland. Of the 47 patients who had a total of 117 acute attacks during the period 1967-1989, 6 died during an attack and 21 attacks were associated with paresis; the frequency of severe attacks was significantly smaller than before 1967 (p = 0.00002). Most pareses and deaths occurred because of a delay in diagnosis and inappropriate treatment of porphyria. For those patients who were symptom-free at the time of diagnosis (1365 follow-up years), the risk of the first subsequent attack was significantly smaller than for those who had had an acute attack before the diagnosis of porphyria (1047 follow-up years, p = 0.005). In addition, milder symptoms of porphyria were more common among those who had had previous attacks than among those who had not (p less than 0.00001). In AIP the risk of attacks correlated with the excretion of porphobilinogen in the urine during remission among adults (p = 0.03); a low rate of excretion predicted freedom from acute attacks. A regular use of many precipitating drugs was never associated with symptoms of porphyria. Two percent of the surgical operations and 4% of the pregnancies were associated with acute attacks. Nearly one-third of the women had symptoms of porphyria associated with the menstrual cycle, but these seldom proceeded to an acute attack. Forty-six percent of the women had used sex-hormone preparations regularly; 2 of them (4.5%) experienced associated acute attacks. Patients with AIP or VP showed increased incidences of hepatocellular carcinoma, and probably also chronic renal failure and hypertension.

Clinical and biochemical characteristics and genotype–phenotype correlation in Finnishvariegate porphyria patients

Variegate porphyria (VP) is an inherited metabolic disease resulting from the partial deficiency of protoporphyrinogen oxidase, the penultimate enzyme in the heme biosynthetic pathway. We have evaluated the clinical and biochemical outcome of 103 Finnish VP patients diagnosed between 1966 and 2001. Fifty-two per cent of patients had experienced clinical symptoms: 40% had photosensitivity, 27% acute attacks and 14% both manifestations. The proportion of patients with acute attacks has decreased dramatically from 38 to 14% in patients diagnosed before and after 1980, whereas the prevalence of skin symptoms had decreased only subtly from 45 to 34%. We have studied the correlation between PPOX genotype and clinical outcome of 90 patients with the three most common Finnish mutations I12T, R152C and 338G→C. The patients with the I12T mutation experienced no photosensitivity and acute attacks were rare (8%). Therefore, the occurrence of photosensitivity was lower in the I12T group compared to the R152C group (P=0.001), whereas no significant differences between the R152C and 338G→C groups could be observed. Biochemical abnormalities were significantly milder suggesting a milder form of the disease in patients with the I12T mutation. In all VP patients, normal excretion of protoporphyrin in faeces in adulthood predicted freedom from both skin symptoms and acute attacks. The most valuable test predicting an increased risk of symptoms was urinary coproporphyrin, but only a substantially increased excretion exceeding 1000 nmol/day was associated with an increased risk of both skin symptoms and acute attacks. All patients with an excretion of more than 1000 nmol/day experienced either skin symptoms, acute attacks, or both.

An update of clinical management of acute intermittent porphyria.

Acute intermittent porphyria (AIP) is due to a deficiency of the third enzyme, the hydroxymethylbilane synthase, in heme biosynthesis. It manifests with occasional neuropsychiatric crises associated with overproduction of porphyrin precursors, aminolevulinic acid and porphobilinogen. The clinical criteria of an acute attack include the paroxysmal nature and various combinations of symptoms, such as abdominal pain, autonomic dysfunction, hyponatremia, muscle weakness, or mental symptoms, in the absence of other obvious causes. Intensive abdominal pain without peritoneal signs, acute peripheral neuropathy, and encephalopathy usually with seizures or psychosis are the key symptoms indicating possible acute porphyria. More than fivefold elevation of urinary porphobilinogen excretion together with typical symptoms of an acute attack is sufficient to start a treatment. Currently, the prognosis of the patients with AIP is good, but physicians should be aware of a potentially fatal outcome of the disease. Mutation screening and identification of type of acute porphyria can be done at the quiescent phase of the disease. The management of patients with AIP include following strategies: A, during an acute attack: 1) treatment with heme preparations, if an acute attack is severe or moderate; 2) symptomatic treatment of autonomic dysfunctions, polyneuropathy and encephalopathy; 3) exclusion of precipitating factors; and 4) adequate nutrition and fluid therapy. B, during remission: 1) exclusion of precipitating factors (education of patients and family doctors), 2) information about on-line drug lists, and 3) mutation screening for family members and education about precipitating factors in mutation-positive family members. C, management of patients with recurrent attacks: 1) evaluation of the lifestyle, 2) evaluation of hormonal therapy in women, 3) prophylactic heme therapy, and 4) liver transplantation in patients with severe recurrent attacks. D, follow-up of the AIP patients for long-term complications: chronic hypertension, chronic kidney insufficiency, chronic pain syndrome, and hepatocellular carcinoma.

Clinical and biochemical characteristics and genotype-phenotype correlation in 143 Finnish and Russian patients with acute intermittent porphyria

Abstract: Acute intermittent porphyria (AIP), resulting from a deficiency of porphobilinogen deaminase (PBGD) in heme biosynthesis, is genetically heterogeneous and manifests with variable penetrance. The clinical outcome, prognosis, and correlation between PBGD genotype and phenotype were investigated in 143 Finnish and Russian AIP patients with 10 mutations (33G→T, 97delA, InsAlu333, R149X, R167W, R173W, R173Q, R225G, R225X, 1073delA). Thirty-eight percent of the patients had experienced 1 or more acute attacks during their lives. The proportion of symptomatic patients has decreased dramatically from 49% to 17% among patients diagnosed before and after 1980, respectively. Patients with the R167W and R225G mutations showed lower penetrance (19% and 11%, respectively) and recurrence rate (33% and 0%, respectively) than patients with other mutations (range, 36%-67% and 0%-66%, respectively). Moreover, urinary excretions of porphyrins and their precursors were significantly lower in these patients (porphobilinogen [PBG], 47 ± 10 vs. 163 ± 21 μmol/L, p < 0.001; uroporphyrin, 130 ± 40 vs. 942 ± 183 nmol/d, p < 0.001). Erythrocyte PBGD activity did not correlate with PBG excretion in remission or with the clinical severity of the disease. Mutations R167W and R225G resulted in milder biochemical abnormalities and clinical symptoms indicating a milder form of AIP in these patients. In all AIP patients, normal PBG excretion predicted freedom from acute attacks. The risk of symptoms was highest for female patients with markedly increased PBG excretion (>100 μmol/L). Proper counseling contributed to the prevention of subsequent attacks in 60% of previously symptomatic and in 95% of previously symptom-free patients. Abbreviations: AIP = acute intermittent porphyria, ALA = aminolevulinic acid, ALAS = aminolevulinic acid synthase, PBG = porphobilinogen, PBGD = porphobilinogen deaminase.

Treatment of the Porphyrias

There are seven porphyrias which are caused by defective functions of the enzymes in the haem biosynthesis. Pathogenic mechanisms and symptoms differ greatly in individual porphyrias and, consequently, most of them require a specific therapy. Clinically, the three most important entities are acute porphyric attack, porphyria cutanea tarda and protoporphyria. For an acute porphyric attack the treatment of choice is administration of haem; the other measures are elimination of precipitating factors and symptomatic therapy for many associated symptoms. Porphyria cutanea tarda is controlled by removal of iron by phlebotomies or with low-dose chloroquine. Skin symptoms in protoporphyria can be alleviated with betacaroten but there is no effective procedure to normalize disturbed porphyrin metabolism; hepatic failure seen in some patients may need a liver transplantation. The only effective treatment in congenital erythropoietic porphyria is probably a bone marrow transplantation. No satisfactory treatment is available for very rare delta-aminolevulinic acid dehydrase deficiency porphyria.

Diagnostic strategy, genetic diagnosis and identification of new mutations in intermittent porphyria by denaturing gradient gel electrophoresis.

Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease of heme metabolism caused by mutations in the hydroxymethylbilane synthase gene. Diagnosing AIP during an acute attack using traditional biochemical markers is unproblematic, but it can be difficult to obtain a definite diagnosis in asymptomatic carriers. These limitations may, however, be solved through a genetic approach for diagnosing AIP carrier status. A mutation screening assay based on the denaturing gradient gel electrophoresis (DGGE) principle was established in a setup that allows within 24 hr to pinpoint which of the 15 exons of the hydroxymethylbilane synthase gene carries the underlying mutation, and thereby reduces subsequent sequencing, needed to determine the specific mutation, to this particular gene region. To evaluate sensitivity and specificity of the DGGE assay, samples from 22 AIP patients with known mutations and six healthy controls were examined in a blinded design. Following unblinding, it was revealed that in all 22 AIP samples the correct mutation carrying region had been pointed out. In two samples containing a previously undescribed polymorphism, this additional region was also pointed out. All controls were correctly characterized as normal in the DGGE assay. Subsequently, to evaluate the assay in the clinical setting, samples from six previously uncharacterized Danish AIP probands were examined and the underlying mutation detected in all six. In conclusion, a simple and sensitive mutation screening assay based on the DGGE principle allows genetic diagnosis of AIP in a routine setting and may be used as an additional tool in genetic counseling of AIP families. Hum Mutat 9:122–130, 1997.

Clinical features predictive of a poor prognosis in acute porphyria.

Sirs: Acute intermittent porphyria (AIP) is an inherited metabolic disease due to a deficiency of the third enzyme, porphobilinogen deaminase, in heme biosynthesis. Acute porphyrias manifest as acute attacks including a combination of autonomic and peripheral neuropathy and CNS involvement accompanied by increased excretion of porphyrin precursors [4, 13]. Scales designed for other peripheral neuropathies [1–3] are unsuitable for AIP, and we therefore developed a clinical scale predictive of a prognosis of AIP patients. The prospective study of clinical manifestations and outcome of an acute attack of 12 Russian AIP patients were used as a database for regression analysis. The diagnosis of AIP was unknown to the patients before their admission to the hospitals in north-western Russia during 1995–2001 (Table 1). AIP was confirmed by biochemical analyses and DNA testing [9]. Muscle strength was evaluated in six muscle groups on both sides according to the MRC scale from 0 to 5 grade [5, 11, 12] (Table 2) and expressed as MRC sum of scores with a maximum of 60 [11]. We transformed this value to a motor score ranging from 0 to 6. The patients were grouped I–III according to their outcome (Table 1). Signs and symptoms were initially scored according to their clinical importance. The follow-up of the patients ranged from 3 to 9 years (mean 6.5). Dysautonomia manifested as abdominal pain (83 %), tachycardia (92 %), hypertension (67 %) and constipation (75 %). The commonest neurological sign was acute motor polyneuropathy (83 %) often associated with neuropathic sensory loss (42 %) and CNS involvement (92 %) (Table 1). Acute attacks were treated with glucose-infusions (n = 7) [15] or heme arginate (n = 5) [13] after the diagnosis of AIP was confirmed (Group I: 4–27 days, mean 14, Group II: 8–47 days, mean 21, Group III: 38–49 days, mean 44, p = 0.05). Regression analysis with a maximum group discrimination as an optimisation criterion [10] was employed to evaluate an association with outcome variables (the prognosis of a patient) and covariates (symptoms and signs of an acute attack), which were normalised from 0 to 1, and a sum of α2 = 1 resulted in one solution only for each regression coefficient (α). The symptoms and signs that showed no significant step-wise increase between groups I–III were excluded and scored 0. For the covariates X1–X5, the coefficients α had approximately the same value (~0.40–0.50, Table 2) and therefore they were assigned similarly in our scoring system. Each of them was graded from 0 to 6 comparable to the 0–6 scale initially chosen for the muscle strength. The total score for each patient is a sum of scores gained from all manifestations selected (Table 2). The total score < 5 was compatible with a recovery within 6 months, a score 5–25 suggested recovery delay beyond 6 months or the presence of residual neurological deficits, a score > 25 predicted fatal outcome (Group I: 0–3 scores, mean 1.75, Group II: 6–24 scores, mean 13, Group III: 29–30 scores, mean 29.5, p = 0.0006). Although pain, mental symptoms and tachycardia had no effect on the prognosis, assessment of pain [7] and pulse [14] are useful tools to evaluate the activity and recovery from a mild acute attack. Because of the small number of our patients, no final conclusions can be drawn for the prognostic value of arrhythmia, which can be fatal. MRC scoring is important, since mild or moderate muscle weakness can easily be neglected in the clinical examination. The extent of muscle weakness, mechanical ventilation, bulbar palsy, consciousness impairment and hyponatremia correlated with a poor outcome of a potentially fatal acute attack [6, 8] and may be evaluated in a clinically useful scoring system, which allows comparisons of acute attacks between different patient series.

Diagnosis of variegate porphyria--hard to get?

Variegate porphyria (VP) is an inherited metabolic disease that results from the partial deficiency of protoporphyrinogen oxidase. In this communication we have used DNA technology in the diagnosis of VP and compared the results with the biochemical and clinical data. To date, we have diagnosed 107 VP patients using either biochemical or DNA techniques or both. In addition, in 106 family members the diagnosis of VP could be excluded. The sensitivity and specificity of the biochemical screening for VP were studied among 38 family members. These individuals were either asymptomatic (n=19) or had experienced occasional skin symptoms (n=13), acute attacks (n=5) or both (n=1). The sensitivity of urinary and fecal coproporphyrin analysis was 48% and 52%, respectively. The sensitivity of urinary uroporphyrin analysis was 71% and for fecal protoporphyrin 77%. Plasma fluorescence was sensitive in symptomatic patients even in remission, but resulted in false negatives in four asymptomatic patients with normal excretion of porphyrins in the urine. In our series of mutation screening, many new asymptomatic patients were identified, and this demonstrated that DNA analysis is the only reliable way to screen (a)symptomatic patients facilitating correct treatment and proper genetic counselling of family members at risk. Biochemical analyses (e.g. plasma fluorescence, fecal protoporphyrins, urinary copro- and uroporphyrins, porphobilinogen and delta-aminolevulinic acid) are essential when the diagnosis of VP is confirmed at the symptomatic phase.Variegate porphyria (VP) is an inherited metabolic disease that results from the partial deficiency of protoporphyrinogen oxidase. In this communication we have used DNA technology in the diagnosis of VP and compared the results with the biochemical and clinical data. To date, we have diagnosed 107 VP patients using either biochemical or DNA techniques or both. In addition, in 106 family members the diagnosis of VP could be excluded. The sensitivity and specificity of the biochemical screening for VP were studied among 38 family members. These individuals were either asymptomatic (n = 19) or had experienced occasional skin symptoms (n = 13), acute attacks (n = 5) or both (n = 1). The sensitivity of urinary and fecal coproporphyrin analysis was 48% and 52%, respectively. The sensitivity of urinary uroporphyrin analysis was 71% and for fecal protoporphyrin 77%. Plasma fluorescence was sensitive in symptomatic patients even in remission, but resulted in false negatives in four asymptomatic patients with normal excretion of porphyrins in the urine. In our series of mutation screening, many new asymptomatic patients were identified, and this demonstrated that DNA analysis is the only reliable way to screen (a)symptomatic patients facilitating correct treatment and proper genetic counselling of family members at risk. Biochemical analyses (e.g. plasma fluorescence, fecal protoporphyrins, urinary copro- and uroporphyrins, porphobilinogen and delta-aminolevulinic acid) are essential when the diagnosis of VP is confirmed at the symptomatic phase.

Is screening for urinary porphobilinogen useful among patients with acute polyneuropathy or encephalopathy

Acute porphyrias are a group of inherited metabolic disorders representing overproduction syndromes with the formation of neurotoxic haem precursors. Clinical manifestations consist of acute attacks, which include abdominal pain, dysautonomia, mental symptoms, polyneuropathy and seizures mimicking many other acute neurological disorders. Porphyrin metabolites were screened in 108 patients with acute polyneuropathy or encephalopathy associated with pain and/or dysautonomia, who attended neurological wards, in order to evaluate the number of patients with acute porphyria. Urinary porphyrins and their precursors were increased in 21 % of the cases. Surprisingly many patients (11 %) had previously undiagnosed acute porphyria. Half of these patients had had mild to moderate symptoms of acute porphyria previously. Secondary porphyrinuria, which was mainly transient coproporphyrinuria because of hepatopathy, was also common (10 %). Of the 108 patients studied, the levels of urinary porphyrins or their precursors were normal in the majority (79 %) of the cases, who commonly had Guillain-Barré syndrome (40 %). Epileptic seizures were also frequent (18 %), but none of the patients with acute porphyria had solely epileptic seizures without prolonged confusion (≥ 1 day). Based on our findings, acute inherited porphyria is not infrequent among the selected group of neurological patients and screening of urinary PBG is cost-beneficial. Since the correct diagnosis of a hereditary disease is essential, genetic screening should be performed whenever possible for patients with clinically and biochemically confirmed acute porphyria.Acute porphyrias are a group of inherited metabolic disorders representing overproduction syndromes with the formation of neurotoxic haem precursors. Clinical manifestations consist of acute attacks, which include abdominal pain, dysautonomia, mental symptoms, polyneuropathy and seizures mimicking many other acute neurological disorders.Porphyrin metabolites were screened in 108 patients with acute polyneuropathy or encephalopathy associated with pain and/or dysautonomia, who attended neurological wards, in order to evaluate the number of patients with acute porphyria.Urinary porphyrins and their precursors were increased in 21 % of the cases. Surprisingly many patients (11 %) had previously undiagnosed acute porphyria. Half of these patients had had mild to moderate symptoms of acute porphyria previously. Secondary porphyrinuria, which was mainly transient coproporphyrinuria because of hepatopathy, was also common (10 %). Of the 108 patients studied, the levels of urinary porphyrins or their precursors were normal in the majority (79 %) of the cases, who commonly had Guillain-Barré syndrome (40 %). Epileptic seizures were also frequent (18 %), but none of the patients with acute porphyria had solely epileptic seizures without prolonged confusion (≥ 1 day).Based on our findings, acute inherited porphyria is not infrequent among the selected group of neurological patients and screening of urinary PBG is cost-beneficial. Since the correct diagnosis of a hereditary disease is essential, genetic screening should be performed whenever possible for patients with clinically and biochemically confirmed acute porphyria.

Potential Role of Oxidative Damage in Neurological Manifestations of Acute Intermittent Porphyria

Accumulation of 5-aminolevulinic acid (ALA) is the main defect in acute porphyria and the most likely potential candidate to cause acute neurological manifestations during an acute porphyric attack via multiple direct and indirect mechanisms. ALA is a potential endogenous source of reactive oxygen species (ROS). After administration of ALA or inducers of ALA-synthase in in vitro conditions or in animal models, the main pro-oxidants detected have been superoxide, hydrogen peroxide, hydroxyl radicals, and 4,5-dioxovaleric acid (DOVA), which has produced oxidative damage (OD) to lipids, proteins, and DNA. At the organelle level, ALA-induced OD affects the permeability of the biological membranes, probably as a result of protein polymerization and lipid peroxidation. In vitro exposure to ALA has caused OD to Schwann cells and inhibited myelin formation. Magnetic resonance imaging (MRI) of patients with acute intermittent porphyria (AIP) who suffer from severe reversible posterior encephalopathy syndrome (PRES) during the acute attack shows features of impaired permeability of the blood–brain barrier (BBB); this could be the result of oxidative stress (OS) allowing neurotoxins such as ALA to damage neurons. Peripheral demyelination found in heterozygote or homozygote patients with AIP could be caused by direct OD caused by ALA, which produces pro-oxidants that may affect Schwann cells and myelin. Because ALA is not the most potent pro-oxidant, the OD is only a minor contributor to the neurological manifestations of AIP in general. It could, however, explain the fact that encephalopathy and peripheral demyelination are present only during severe attacks of AIP, in which the high level of serum ALA results in significant auto-oxidation.