Brain ventricular enlargement in human and murine acute intermittent porphyria.

The morphological changes that occur in the central nervous system of patients with severe acute intermittent porphyria (AIP) have not yet been clearly established. The aim of this work was to analyze brain involvement in patients with severe AIP without epileptic seizures or clinical posterior reversible encephalopathy syndrome, as well as in a mouse model receiving or not liver-directed gene therapy aimed at correcting the metabolic disorder. We conducted neuroradiologic studies in 8 severely affected patients (6 women) and 16 gender- and age-matched controls. Seven patients showed significant enlargement of the cerebral ventricles and decreased brain perfusion was observed during the acute attack in two patients in whom perfusion imaging data were acquired. AIP mice exhibited reduced cerebral blood flow and developed chronic dilatation of the cerebral ventricles even in the presence of slightly increased porphyrin precursors. While repeated phenobarbital-induced attacks exacerbated ventricular dilation in AIP mice, correction of the metabolic defect using liver-directed gene therapy restored brain perfusion and afforded protection against ventricular enlargement. Histological studies revealed no signs of neuronal loss but a denser neurofilament pattern in the periventricular areas, suggesting compression probably caused by imbalance in cerebrospinal fluid dynamics. In conclusion, severely affected AIP patients exhibit cerebral ventricular enlargement. Liver-directed gene therapy protected against the morphological consequences of the disease seen in the brain of AIP mice. The observational study was registered at Clinicaltrial.gov as NCT02076763.

Severe hydroxymethylbilane synthase deficiency causes depression-like behavior and mitochondrial dysfunction in a mouse model of homozygous dominant acute intermittent porphyria.

Acute intermittent porphyria (AIP) is an autosomal dominant inborn error of heme biosynthesis due to a pathogenic mutation in the Hmbs gene, resulting in half-normal activity of hydroxymethylbilane synthase. Factors that induce hepatic heme biosynthesis induce episodic attacks in heterozygous patients. The clinical presentation of acute attacks involves the signature neurovisceral pain and may include psychiatric symptoms. Here we used a knock-in mouse line that is biallelic for the Hmbs c.500G > A (p.R167Q) mutation with ~ 5% of normal hydroxymethylbilane synthase activity to unravel the consequences of severe HMBS deficiency on affective behavior and brain physiology. Hmbs knock-in mice (KI mice) model the rare homozygous dominant form of AIP and were used as tool to elucidate the hitherto unknown pathophysiology of the behavioral manifestations of the disease and its neural underpinnings. Extensive behavioral analyses revealed a selective depression-like phenotype in Hmbs KI mice; transcriptomic and immunohistochemical analyses demonstrated aberrant myelination. The uncovered compromised mitochondrial function in the hippocampus of knock-in mice and its ensuing neurogenic and neuroplastic deficits lead us to propose a mechanistic role for disrupted mitochondrial energy production in the pathogenesis of the behavioral consequences of severe HMBS deficiency and its neuropathological sequelae in the brain.

Penetrance and predictive value of genetic screening in acute porphyria.

OBJECTIVE: Penetrance, predictive value and female patients' perspectives on genetic testing were evaluated among Finnish patients with acute porphyria. We conducted a retrospective study to evaluate prognosis among at-risk female family members depending on the primary method of diagnosis. METHODS: The penetrance was calculated among 23 genetically heterogeneous families selected from the Finnish porphyria registry (n = 515, AIP 333; VP 182). We included kindreds with ≥9 patients in a family (range 9-23 patients, total 216 AIP; 129 VP). In 2015, the registry included 164 living female subjects between 14 and 85 years of age. A questionnaire was sent to 143 women, of whom 107 (75%, AIP 67; VP 40) replied. Female at-risk relatives (AIP 54; VP 30) were divided into two groups based on the primary method of diagnosis: mutation analysis (Group A, n = 40) or biochemical analysis (Group B, n = 44). RESULTS: Mean penetrance for all acute symptoms was 35% among AIP and 40% among VP families. In both study groups, the penetrance was higher among female (AIP 50%; VP 44%) than male patients (AIP 17%; VP 33%). Penetrance for hospitalized attacks was 30% among AIP families (range 10-80%, for women 41%) and 25% in VP (range 0-50%, for women 27%) demonstrating wide variations among families even with the similar genotype. Acute porphyria was diagnosed at the median age of 26 years (range 0-76 years) among female patients, commonly after the onset of acute symptoms. Diagnostic delay was an average of 7.4 years (range 1-30 years). Acute symptoms occurred at the median age of 24 years (range 10-57 years) and the first hospitalization at the median age of 26.5 years (range 15-57 years). At the onset of symptoms, 38% of the women were ≤ 20 years of age. According to the life table analysis, acute attacks occurred mainly during the following five years after the diagnosis and the attack risk diminished after 35 years of age. The annual risk for hospitalization due to an acute attack during fertile years was lower in Group A than Group B (0.002 vs. 0.010, p = .018), but the risk of all subsequent acute symptoms did not diminish (Group A 0.017 vs. Group B 0.019, p = .640). The cumulative risk of acute symptoms among asymptomatic patients at the time of diagnosis was 26.7% for Group A and 58.3% for Group B. The cumulative risk of the first subsequent attack requiring hospitalization after the diagnosis among all at-risk relatives was similarly less frequent in Group A than in Group B (OR 0.180; 95% CI 0.041-0.789, p = .041). If attacks were followed among symptomatic patients only, attack-free years were more frequent in Group A than in Group B. Patients preferred genetic screening before puberty to minimize the risk of acute symptoms and genetic discrimination was rare. 44% of the patients reported social, psychological or physical impairment due to acute hepatic porphyria, emphasizing the importance of supporting patients' emotional and resilience capacity. CONCLUSIONS: Among female at-risk relatives the annual risk for hospitalization due to an acute attack is <1% and for acute symptoms <2% during the fertile years. Genetic testing of relatives diminishes the risk of acute attacks. Diagnosis before symptom onset is key for subjects to remain asymptomatic during follow-up, and genetic screening should be done earlier than currently.

Acute intermittent porphyria: analgesia can be dangerous.

Acute intermittent porphyria (AIP) is a rare condition, a metabolic disorder of the haem biosynthesis. An acute crisis of AIP can present as a combination of symptoms, such as abdominal pain, autonomic dysfunction, hyponatremia, muscle weakness and neurological symptoms in the absence of others obvious causes. We report the case of a 53-year-old woman, who was previously diagnosed with AIP 5 weeks after therapeutic suspension has developed an acute disease exacerbation. During hospitalisation, further exacerbation has occurred after analgesia with metamizole. Glucose and hemin infusions resulted in slow improvement. Physical rehabilitation was crucial to peripheral polyneuropathy recovery. Taking into account the porphyrinogenic effect described for metamizole, this drug might have triggered the second attack. Clinical history was sufficient to suspect the diagnosis and to start the treatment immediately, preventing important sequelae.

International Porphyria Molecular Diagnostic Collaborative: an evidence-based database of verified pathogenic and benign variants for the porphyrias.

With the advent of precision and genomic medicine, a critical issue is whether a disease gene variant is pathogenic or benign. Such is the case for the three autosomal dominant acute hepatic porphyrias (AHPs), including acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria, each resulting from the half-normal enzymatic activities of hydroxymethylbilane synthase, coproporphyrinogen oxidase, and protoporphyrinogen oxidase, respectively. To date, there is no public database that documents the likely pathogenicity of variants causing the porphyrias, and more specifically, the AHPs with biochemically and clinically verified information. Therefore, an international collaborative with the European Porphyria Network and the National Institutes of Health/National Center for Advancing Translational Sciences/National Institute of Diabetes and Digestive and Kidney Diseases (NIH/NCATS/NIDDK)-sponsored Porphyrias Consortium of porphyria diagnostic experts is establishing an online database that will collate biochemical and clinical evidence verifying the pathogenicity of the published and newly identified variants in the AHP-causing genes. The overall goal of the International Porphyria Molecular Diagnostic Collaborative is to determine the pathogenic and benign variants for all eight porphyrias. Here we describe the overall objectives and the initial efforts to validate pathogenic and benign variants in the respective heme biosynthetic genes causing the AHPs.

Acute intermittent porphyria presenting with seizures and posterior reversible encephalopathy syndrome: Two case reports and a literature review.

INTRODUCTION: Acute intermittent porphyria (AIP) is a rare and challenging hereditary neurovisceral disease with no specific symptoms. Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological syndrome with bilateral reversible posterior gyriform lesions that can be associated with many different conditions, including AIP. Usually, peripheral neuropathy is considered the most common neurological manifestation of AIP. However, AIP should also be considered when seizures and PRES are associated with unexplained abdominal pain. CASE PRESENTATION: Both the patients were presented with seizures and PRES on brain magnetic resonance imaging (MRI). Unexplained abdominal pain occurred before the onset of seizures. The AIP diagnosis was made after repeated Watson-Schwartz tests. Hematin was not available for these 2 patients. However, supportive treatment including adequate nutrition and fluid therapy as well as specific antiepileptic drugs aided the patient's recovery and no acute attacks had occurred by the 3-year follow-up. CONCLUSION: In contrast to other causes of PRES patients, seizure is the most common symptom in AIP patients with PRES. This is a strong diagnostic clue for AIP when ambiguous abdominal pain patients presented with seizures and PRES on brain MRI. A positive prognosis can be achieved with the combination of early recognition, supportive and intravenous hematin therapy, and withdrawal of precipitating factors, including some antiepileptic drugs.

Patient Perspective on Acute Intermittent Porphyria with Frequent Attacks: A Disease with Intermittent and Chronic Manifestations.

OBJECTIVE: Acute intermittent porphyria is a rare metabolic disorder that affects heme synthesis. Patients with acute intermittent porphyria may experience acute debilitating neurovisceral attacks that require frequent hospitalizations and negatively impact quality of life. Although clinical aspects of acute intermittent porphyria attacks have been documented, the experience of patients is not well known, particularly for those more severely affected patients who experience frequent attacks. The aim of the present study was to qualitatively characterize the experience of patients with acute intermittent porphyria who have frequent attacks, as well as the impact of the disease on daily living. METHODS: Patients with acute intermittent porphyria who experience frequent attacks were recruited and took part in 2-h qualitative one-on-one interviews with a semi-structured guide. Interviews were anonymized, transcribed, and coded. The inductive coding approach targeted textual data related to acute intermittent porphyria attack symptoms, chronic symptoms, and the impact of the disease. Saturation analysis was conducted to assess whether the research elicited an adequate account of patients' experiences. RESULTS: In total, 19 patients with acute intermittent porphyria were interviewed (mean age 40 years; 79% female). Eighteen patients (95%) experienced both attack and chronic symptoms. Patients described attacks as the onset of unmanageable symptoms that generally lasted 3-5 days requiring hospitalization and/or treatment. Pain, nausea, and vomiting were considered key attack symptoms; pain, nausea, fatigue, and aspects of neuropathy (e.g., tingling and numbness) were considered key chronic symptoms. CONCLUSIONS: In this study population of acute intermittent porphyria with frequent attacks, most patients had symptoms during and between attacks. In these patients, acute intermittent porphyria appears to have acute exacerbations as well as chronic day-to-day manifestations, and is not just intermittent as its name implies. As a result, patients reported limitations in their ability to function across multiple domains of their lives on a regular basis and not just during acute attacks.

Recurrent attacks of acute hepatic porphyria: major role of the chronic inflammatory response in the liver.

BACKGROUND: Acute intermittent porphyria (AIP) is an inherited disorder of haem metabolism characterized by life-threatening acute neurovisceral attacks due to the induction of hepatic δ-aminolevulinic acid synthase 1 (ALAS1) associated with hydroxymethylbilane synthase (HMBS) deficiency. So far, the treatment of choice is hemin which represses ALAS1. The main issue in the medical care of AIP patients is the occurrence of debilitating recurrent attacks. OBJECTIVE: The aim of this study was to determine whether chronic hemin administration contributes to the recurrence of acute attacks. METHODS: A follow-up study was conducted between 1974 and 2015 and included 602 French AIP patients, of whom 46 had recurrent AIP. Moreover, we studied the hepatic transcriptome, serum proteome, liver macrophage polarization and oxidative and inflammatory profiles of Hmbs-/- mice chronically treated by hemin and extended the investigations to five explanted livers from recurrent AIP patients. RESULTS: The introduction of hemin into the pharmacopeia has coincided with a 4.4-fold increase in the prevalence of chronic patients. Moreover, we showed that both in animal model and in human liver, frequent hemin infusions generate a chronic inflammatory hepatic disease which induces HO1 remotely to hemin treatment and maintains a high ALAS1 level responsible for recurrence. CONCLUSION: Altogether, this study has important impacts on AIP care underlying that hemin needs to be restricted to severe neurovisceral crisis and suggests that alternative treatment targeting the liver such as ALAS1 and HO1 inhibitors, and anti-inflammatory therapies should be considered in patients with recurrent AIP.

El grupo hemo y la ácido aminolevulínico sintasa 1 en la fisiopatología de los ataques agudos de porfiria / The haem group and aminolaevulinic acid synthase-1 in the pathophysiology of acute porphyria attacks

Las porfirias hepáticas agudas son 4 enfermedades raras causadas por deficiencias enzimáticas en la vía biosintética del grupo hemo. Se caracterizan por presentar síntomas neuroviscerales agudos potencialmente letales ante la presencia de factores inductores de la ALAS1. Estos factores pueden ser endógenos o exógenos tales como hormonas sexuales, ayuno, medicamentos, alcohol y tabaco, entre otros. La fisiopatología de los ataques involucra el incremento en la función de la ALAS1, la producción excesiva de precursores de porfirina y la alteración en la síntesis de hemoproteínas por la deficiencia relativa de hemo. En este artículo se revisa la interacción de esos mecanismos con algunos factores inductores, su papel en el origen de los síntomas neurológicos y cómo los tratamientos disponibles bloquean estos procesos (AU)

The acute hepatic porphyrias are a group of 4 rare diseases caused by enzymatic deficiencies in the haem biosynthetic pathway. They are characterized by presenting acute attacks of neurovisceral symptoms in presence of factors that increase the ALAS1 activity. Those factors could be endogenous or exogenous, such as sexual hormones, fasting, drugs, alcohol, tobacco, among other. The physiopathology of the attacks involves an increasing in ALAS1 function, excessive production of porphyrin precursors, and disturbances in hemoproteins synthesis due to the relative haem deficiency. The present paper is a review of the interaction of those mechanisms with some factors that induce ALAS1, their role in the origin of neurovisceral symptoms, and how the available treatments interfere with those processes (AU)

Acute Intermittent Porphyria in children: A case report and review of the literature.

Acute Intermittent Porphyria (AIP), an autosomal dominant inborn error of heme metabolism, typically presents in adulthood, most often in women in the reproductive age group. There are limited reports on the clinical presentation in children, and in contrast to the adults, most of the reported pediatric cases are male. While acute abdominal pain is the most common presenting symptom in children, seizures are commonly seen and may precede the diagnosis of AIP. As an example, we report a 9year old developmentally normal pre-pubertal boy who presented with acute abdominal pain, vomiting and constipation followed by hyponatremia, seizures, weakness and neuropathy. After a diagnostic odyssey, his urine porphobilinogen was found to be significantly elevated and genetic testing showed a previously unreported consensus splice-site mutation IVS4-1G>A in the HMBS gene confirming the diagnosis of AIP. Here, we discuss the clinical presentation in this case, and 15 reported pediatric cases since the last review 30years ago and discuss the differential diagnosis and challenges in making the diagnosis in children. We review the childhood-onset cases reported in the Longitudinal Study of the Porphyrias Consortium. Of these, genetically and biochemically confirmed patients, 11 of 204 (5%) reported onset of attacks in childhood. Most of these patients (91%) reported recurrent attacks following the initial presentation. Thus, AIP should be considered in the differential diagnosis of children presenting with unexplained abdominal pain, seizures, weakness and neuropathy.

Light-induced depigmentation in planarians models the pathophysiology of acute porphyrias.

Porphyrias are disorders of heme metabolism frequently characterized by extreme photosensitivity. This symptom results from accumulation of porphyrins, tetrapyrrole intermediates in heme biosynthesis that generate reactive oxygen species when exposed to light, in the skin of affected individuals. Here we report that in addition to producing an ommochrome body pigment, the planarian flatworm Schmidtea mediterranea generates porphyrins in its subepithelial pigment cells under physiological conditions, and that this leads to pigment cell loss when animals are exposed to intense visible light. Remarkably, porphyrin biosynthesis and light-induced depigmentation are enhanced by starvation, recapitulating a common feature of some porphyrias - decreased nutrient intake precipitates an acute manifestation of the disease. Our results establish planarians as an experimentally tractable animal model for research into the pathophysiology of acute porphyrias, and potentially for the identification of novel pharmacological interventions capable of alleviating porphyrin-mediated photosensitivity or decoupling dieting and fasting from disease pathogenesis.

Efecto a largo plazo de las infusiones de hematina en el desarrollo de enfermedad renal crónica en la porfiria aguda intermitente / Influence of long-term treatment with hemin in the development of chronic renal failure in acute intermittent porphyria

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[Plasma and salivary markers of oxidative and carbonyl stress in patients with acute intermittent porphyria]. / Markery oxidacného a karbonylového stresu v plazme a slinách u chorých s akútnou intermitentnou porfýriou.

BACKGROUND: Acute intermittent porphyria (AIP) is an autosomal inherited disease caused by deficiency of the third enzyme in the heme biosynthetic pathway, porphobilinogen deaminase. The clinical course of the disease is characterized by acute attacks, most often with abdominal pain.The aim of our study was to investigate selected markers of oxidative and carbonyl stress in plasma and saliva in patients with AIP and to find out whether saliva could be used for monitoring the disease progression. Saliva is an attractive biological fluid for determination of biochemical markers in various pathological conditions. The advantage is that saliva can be collected non-invasively, and the examination needs only a small volume of saliva. METHODS: Blood and total non-stimulated saliva were collected from 16 patients with AIP in remission, and from 20 healthy individuals. Markers of oxidative and carbonyl stress - advanced glycation end products (AGEs), and thiobarbituric acid reacting substances (TBARS) were determined by spectrofluorometric methods, advanced oxidation protein products (AOPPs), total antioxidant capacity (TAC) and ferric reducing ability of plasma/saliva (FRAP/FRAS) were investigated by spectrophotometric methods in the above mentioned groups. RESULTS: Advanced glycation end products and thiobarbituric acid reacting substances in plasma and saliva were significantly higher in patients with AIP in comparison to the control group (p < 0.001) and (p < 0.05). Advanced oxidation protein products in AIP if compared to the control group did not show statistical significance (p > 0.05), but the levels in the saliva were significantly lower (p < 0.001). The concentrations of markers of antioxidant status of plasma and saliva were significantly lower in AIP if compared to the control group (p < 0.001). CONCLUSIONS: According to the best of our knowledge this is the first study to demonstrate increased concentrations of markers of oxidative and carbonyl stress and decreased antioxidant status of plasma and saliva in patients with AIP. Moreover, the study suggests that the saliva might be a promising fluid to study relevant biomarkers in a wide array of human biomedical conditions.Key words: acute intermittent porphyria - biomarkers - oxidative and carbonyl stress - plasma and saliva.

Porfiria aguda intermitente: seguimiento a largo término de 35 pacientes / Acute intermittent porphyria: Long-term follow up of 35 patients

Fundamento y objetivos: La porfiria aguda intermitente (PAI) es una enfermedad causada por un defecto en la enzima porfobilinógeno deaminasa que cataliza la tercera etapa de síntesis del hemo. Los portadores pueden presentar ataques neuroviscerales agudos tras sobreproducción hepática de precursores del hemo. Pacientes y método: Se presentan las características de todos los pacientes con PAI atendidos en el Hospital Clínic de Barcelona entre los años 1993-2013, y su seguimiento a largo plazo. Resultados: Treinta y cinco pacientes con PAI (33 mujeres y 2 varones) presentaron ataques agudos neuroviscerales. El tratamiento con hemina resolvió el cuadro agudo en todos los casos. Nueve pacientes presentaron polineuropatía y secuelas persistentes. El seguimiento permitió clasificar a los pacientes en: A, con sintomatología aguda durante 1-2 años y posterior remisión duradera (n = 24) o bien alguna crisis puntual (n = 3), y B, con ataques recurrentes que requirieron administración crónica de hemina (n = 8). En la mayoría de los pacientes del grupo A la concentración urinaria de precursores del hemo fue disminuyendo progresivamente, mientras que en el grupo B esta se mantuvo elevada sin descenso observable a largo término. Adicionalmente, el estudio familiar permitió identificar 44 portadores asintomáticos, la mayoría (70,5%) con valores normales de precusores del hemo en orina. Conclusiones: Una mayoría de pacientes con PAI de nuestra serie logró una remisión clínica duradera. Una minoría presenta ataques recurrentes, sin que el tratamiento crónico con hemina haga factible su interrupción ni induzca remisión bioquímica a largo plazo. El tipo de mutación en el gen de la porfobilinógeno deaminasa, y también factores asociados al estilo de vida, pueden determinar el curso de la remisión (AU)

Background and objectives: Acute intermittent porphyria (AIP) is a rare disease that results from a deficiency of porphobilinogen deaminase, the third enzyme of the heme biosynthetic pathway. AIP carriers are at risk of presenting acute neurovisceral attacks associated with overproduction of heme-precursors in the liver. Patients and method: We report the characteristics of all AIP patients attended in the Hospital Clinic of Barcelona during the years 1993-2013 and their long-term follow-up. Results: Thirty-five AIP patients (33 women, 2 men) experienced acute attacks. Treatment with hemin resolved the acute neurovisceral crisis in all cases. Nine patients presented peripheral neuropathy and persistent sequelae. Long-term follow-up allowed classifying the patients into groups: A, patients with acute symptoms during 1-2 years and subsequent long-lasting clinical remission (n = 24) or a few sporadic crises (n = 3), and B, patients with recurrent attacks requiring chronic administration of hemin (n = 8). In a majority of the patients of group A, the urinary excretion of heme-precursors decreased gradually over time. However, the chronic hemin regime did not induce a decline of urinary heme-precursors in the patients of group B. Additionally, we identified 44 asymptomatic AIP carriers, most (70.5%) with normal values of heme-precursors in urine. Conclusions: A majority of the AIP patients of our series achieved a long-lasting clinical remission. A minority (23%) presented recurrent attacks that required chronic hemin infusions without feasible interruption and without long-term biochemical remission. The type of mutation within the porphobilinogen deaminase gene and also life-style related factors may determine remission time-course (AU)

Clinical presentation and electrophysiological findings of porphyric neuropathies: a follow-up study.

INTRODUCTION: A case series of acute intermittent porphyria (AIP) is described that focuses on the clinical course of the disease with regard to neurological manifestations of the peripheral nervous system. METHODS: Eight patients were diagnosed with AIP on the basis of characteristic clinical findings, erythrocyte porphobilinogendeaminase activity, neuropathic patterns, serial changes in nerve conduction studies (NCS), and temporal relationship of central nervous system involvement. RESULTS: Six patients diagnosed with AIP<2 months after symptom onset had neuropathy that was predominantly upper extremity, motor, and proximal. NCS recovery rates were slower in the lower than the upper limbs. Two patients diagnosed >2 months after symptom onset had distal sensorimotor polyneuropathy. CONCLUSIONS: The findings from this case series suggest that the peripheral nerves may be differentially and selectively involved in different diagnostic stages of porphyric neuropathy.

Guillain Barré Syndrome, Systemic Lupus Erythematosus and Acute Intermittent Porphyria ­ A Deadly Trio.

Peripheral nervous system involvement occurs in 3-18% patients of systemic lupus erythematosus (SLE) cases. American College of Rheumatology (ACR) includes 19 neuropsychiatric syndromes for diagnosis of SLE divided into neurological syndromes of central, peripheral and autonomic nervous systems along with the psychiatric syndromes. Sensorimotor quadriparesis in a suspected case of SLE could be due to a Guillain Barré (GBS)-like illness, mononeuritis multiplex presenting as plexopathies, an anterior spinal artery syndrome or it can present like an acute transverse myelitis or hypokalemic periodic paralysis related to Sjogren's syndrome with renal tubular acidosis. We here report a case of a fulminant quadriparesis due to a SLE flare which subsequently was also found to be a case of Acute Intermittent Porphyria.