Update on the Porphyrias.

The porphyrias are a group of rare diseases, each resulting from a defect in a different enzymatic step of the heme biosynthetic pathway. They can be broadly divided into two categories, hepatic and erythropoietic porphyrias, depending on the primary site of accumulation of heme intermediates. These disorders are multisystemic with variable symptoms that can be encountered by physicians in any specialty. Here, we review the porphyrias and describe their clinical presentation, diagnosis, and management. We discuss novel therapies that are approved or in development. Early diagnosis is key for the appropriate management and prevention of long-term complications in these rare disorders.

The Hepatic Porphyrias: Revealing the Complexities of a Rare Disease.

The porphyrias are a group of metabolic disorders that are caused by defects in heme biosynthesis pathway enzymes. The result is accumulation of heme precursors, which can cause neurovisceral and/or cutaneous photosensitivity. Liver is commonly either a source or target of excess porphyrins, and porphyria-associated hepatic dysfunction ranges from minor abnormalities to liver failure. In this review, the first of a three-part series, we describe the defects commonly found in each of the eight enzymes involved in heme biosynthesis. We also discuss the pathophysiology of the hepatic porphyrias in detail, covering epidemiology, histopathology, diagnosis, and complications. Cellular consequences of porphyrin accumulation are discussed, with an emphasis on oxidative stress, protein aggregation, hepatocellular cancer, and endothelial dysfunction. Finally, we review current therapies to treat and manage symptoms of hepatic porphyria.

[Acute hepatic porphyrias]. / Akute hepatische Porphyrien.

Acute porphyrias are caused by rare hereditary disorders of hepatic heme biosynthesis. Episodes of accumulating neurotoxic metabolites lead to multisystemic symptoms such as visceral pain, autonomic dysregulation, neurocognitive impairment, hyponatremia, and occasionally motor paralysis. In addition to protracted non-emergency courses, acute life-threatening crises can occur, often triggered by infection, medication, fasting, or hormonal stimuli. Since the clinical presentation is nonspecific and multifaceted, many patients have gone through a long odyssey until they receive a diagnosis. Acute attacks often lead to presenting initially to the emergency department, where acute hepatic porphyria (AHP) is easily overlooked in the differential diagnosis. Establishing the diagnosis requires a high level of genuine suspicion (e.g., cluster of signs and symptoms along with certain patterns of health care resource utilization). The initial diagnostic work-up requires the measurement of metabolites in the urine. Emergency management consists of infusions of glucose and heme arginate along with symptomatic therapy. However, porphyrinogenic agents must be strictly avoided ( www.drugs-porphyria.org ). After initial diagnosis, a thorough work-up should be done at a porphyria center (confirming the diagnosis, education, genetic counselling) and issuance of an emergency identification card is mandatory. If the frequency of relapses is high, new targeted prophylactic therapies have proven effective. Patients with known porphyria require special attention in any acute medical condition in order to avoid porphyrinogenic triggers and to exclude threatening differential diagnosis (e.g., sepsis) by consistent basic diagnostics.

[Advances in the diagnosis and treatment of porphyria-related hepatic manifestations].

Porphyria is a disease caused by defects in the activity of any of the eight enzymes required for the heme synthesis pathway. Most of these are genetic diseases, and the main clinical symptoms are abdominal pain, neuropsychiatric symptoms and skin lesions. Detection of high levels of porphyrin and/or its precursors in blood, urine and feces can be used as diagnostic clues, and known genetic mutations can confirm the diagnosis. Porphyria is rare in clinical practice. However, in recent years, the number of porphyria patients with hepatic disease as the initial symptom has been increasing. Here, we focus on porphyria-related hepatic manifestations and their diagnosis and treatment, so as to provide recommendations for clinicians to reduce the misdiagnosis and missed diagnosis incidence rate.

Neurological Manifestations of Acute Porphyrias.

PURPOSE OF REVIEW: Porphyrias constitute a group of rare metabolic disorders that result in a deficiency of the heme biosynthetic pathway and lead to the accumulation of metabolic intermediaries. Patients with porphyria can experience recurrent neurovisceral attacks which are characterized by neuropathic abdominal pain and acute gastrointestinal symptoms, including nausea, vomiting, and constipation. Depending on the type of porphyria, patients can present with cutaneous manifestations, such as severe skin photosensitivity, chronic hemolysis, or evidence of neurologic dysfunction, including alterations in consciousness, neurovascular involvement, seizures, transient sensor-motor symptoms, polyneuropathy, and behavioral abnormalities. RECENT FINDINGS: More recently, cases of posterior reversible encephalopathy syndrome, cerebral vasoconstriction, and acute flaccid paralysis have also been described. While the exact pathogenic mechanisms linking the accumulation of abnormal heme biosynthetic intermediaries to neurologic manifestations have not been completely elucidated, it has been proposed that these manifestations are more common than previously thought and can result in permanent neurologic injury. This article reviews the basic principles of heme synthesis as well as the pathogenic mechanism of disease, presentation, and treatment of acute hepatic porphyrias with emphasis on those with neurologic manifestations.

The Porphyrias.

The porphyrias are clinically variable and genetically heterogeneous, predominantly hereditary metabolic diseases, which are caused by a dysfunction of specific enzymes in heme biosynthesis. Here, we provide an overview of the etiopathogenesis, clinic, differential diagnosis, laboratory diagnostics and therapy of these complex metabolic disorders and cover in detail the most common form of porphyria worldwide (porphyria cutanea tarda), the most frequent childhood porphyria (erythropoietic protoporphyria), and the most common neurocutaneous porphyria (variegate porphyria).

Expert consensus statement on acute hepatic porphyria in Belgium.

Acute hepatic porphyrias (AHP) are a group of four different rare to ultra-rare, severely debilitating, and sometimes fatal diseases that significantly impact patients' lives: 5-aminolevulinic acid (ALA) dehydratase deficiency porphyria (ADP), acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). Based on literature estimates, a conservative estimate of the number of AHP patients in Belgium requiring treatment, defined as patients experiencing recurrent attacks and/or chronic debilitating symptoms, is likely limited to 11-34 patients. These patients face a considerable unmet need, as there is currently no pharmaceutical treatment available that effectively prevents attacks and has an impact on other chronic symptoms of the disease.A panel consisting of the two European Porphyria Network1 (EPNet) centers in Belgium (Center for inborn errors of metabolism of UZ Leuven and the 'Centre Belge des Porphyries' of Erasme Hospital and LHUB-ULB) participated in an advisory board on 24 January 2020. Representatives of the sponsoring pharmaceutical company, Alnylam Pharmaceuticals, organized and attended the meeting. The objective of the meeting was to obtain expert input on the state-of-the-art clinical practice of AHP in Belgium. Following this meeting, this expert consensus statement was drafted, in collaboration with and coordinated by the EPNet centers in Belgium. This statement provides an overview of the state-of-the art in AHP, by means of a concise overview of AHP pathophysiology, clinical manifestations, and burden of disease, (Belgian) epidemiology, treatments, and proposed organization of care.

Porphyria: awareness is the key to diagnosis!

Porphyrias are disorders of the haem biosynthesis which are encountered infrequently and which often present themselves atypically as a combination of gastrointestinal, neurologic and/or dermatologic symptoms. Although they are primarily caused by enzyme defects, inheritance patterns are mostly not evident. Considering all of these characteristics, it is not surprising that there is a long delay between the onset of symptoms and the diagnosis of the disease, with as possible consequences impaired quality of life, irreversible neurologic damage and even death. This review aims to increase the clinical suspicion of the three most common porphyrias in adults: acute intermittent porphyria (AIP), porphyria cutanea tarda (PCT) and protoporphyria. Their relevant pathophysiology, clinical manifestations, diagnosis and treatment are discussed aiming at increasing the awareness of these diseases among physicians.

[Porphyria]. / Porphyrien.

Porphyrias are caused by enzyme defects along the heme biosynthetic pathway. The first line diagnosis of porphyria is based on specific biochemical patterns of elevated porphyrins and porphyrin precursors in urine, feces, and blood. In clinically active disease accumulated porphyrin precursors and/or porphyrins lead to abdominal, neurologic, psychiatric, endocrine and cardiovascular symptoms, liver damage and/or skin photosensitivity. Porphyrias are classified into acute and nonacute forms. Patients with symptomatic (clinically active) acute hepatic porphyria, e.g. acute intermittent porphyria, porphyria variegata, hereditary coproporphyria, and aminolevulinic acid dehydratase deficiency porphyria, display accumulation of porphyrin precursors, 5­aminolevulinic acid and porphobilinogen due to regulation disorder. In the non-acute forms of porphyria, such as porphyria cutanea tarda, erythropoietic porphyria, X­linked protoporphyria and congenital erythropoietic porphyria, accumulated porphyrins lead to skin photosensitivity and occasionally also to severe liver damage. Several different options for treatment, proven and innovative ones, are available for most porphyrias.

Protocolo de actuación en pacientes con sospecha de porfiria aguda / Protocol for patients with suspected acute porphyria

Las porfirias son errores congénitos del metabolismo de las porfirinas o ruta biosintética del hemo. El acúmulo de los precursores de las porfirinas, ácido delta aminolevulínico (ALA) y/o porfobilinógeno (PBG) es responsable de las crisis neuroviscerales de las porfirias agudas que cuando se expresan clínicamente se inician con intenso dolor abdominal. Durante las crisis la eliminación urinaria de PBG y ALA siempre es muy elevada. La excesiva concentración de PBG en orina es fácilmente identificable mediante el sencillo test de Hoesch. Un test negativo descarta crisis porfírica actual. El protocolo de actuación en pacientes con dolor abdominal agudo no filiado en los que el test de Hoesch positivo permite la sospecha de porfiria aguda se basa en los siguientes aspectos: valoración clínica inicial en el servicio de urgencias, supresión de los posibles factores desencadenantes, tratamiento específico de la crisis con hemina y/o sobrecarga de glucosa y tratamiento sintomático

Porphyrias are a group of congenital errors in porphyrin metabolism and in the heme biosynthetic pathway. Accumulation of porphyrin precursors (delta-aminolaevulinic acid and porphobilinogen) is responsible for the neurovisceral crises of acute porphyria, which, when expressed clinically, start with intense abdominal pain. During crises, the urinary elimination of porphobilinogen and delta-aminolaevulinic acid is always very high. Excessive porphobilinogen concentration in urine is easily identified using the simple Hoesch test. A negative test rules out a current porphyric crisis. The clinical protocol for patients with acute abdominal pain of unknown origin in whom a positive Hoesch test leads to the suspicion of acute porphyria is based on the following aspects: initial clinical assessment in the emergency department, suppression of potential triggers, specific treatment for the crisis with hemin and/or glucose overload and symptomatic treatment

Mutation-Specific Guide RNA for Compound Heterozygous Porphyria On-target Scarless Correction by CRISPR/Cas9 in Stem Cells.

CRISPR/Cas9 is a promising technology for gene correction. However, the edition is often biallelic, and uncontrolled small insertions and deletions (indels) concomitant to precise correction are created. Mutation-specific guide RNAs were recently tested to correct dominant inherited diseases, sparing the wild-type allele. We tested an original approach to correct compound heterozygous recessive mutations. We compared editing efficiency and genotoxicity by biallelic guide RNA versus mutant allele-specific guide RNA in iPSCs derived from a congenital erythropoietic porphyria patient carrying compound heterozygous mutations resulting in UROS gene invalidation. We obtained UROS function rescue and metabolic correction with both guides with the potential of use for porphyria clinical intervention. However, unlike the biallelic one, the mutant allele-specific guide was free of on-target collateral damage. We recommend this design to avoid genotoxicity and to obtain on-target scarless gene correction for recessive disease with frequent cases of compound heterozygous mutations.

Diagnostic and therapeutic strategies for porphyrias.

Porphyrias are rare metabolic disorders. Lack of awareness and knowledge about the clinical features of porphyrias results in diagnostic and therapeutic delays for many patients. Delays in diagnosing and treating porphyrias can result in severe, progressive morbidity (and mortality) and psychological distress for patients. This review discusses the pathophysiology, diagnosis, treatment, and follow-up of the most prevalent porphyrias: acute intermittent porphyria, porphyria cutanea tarda, and erythropoietic protoporphyria.

Neurological and neuropsychiatric manifestations of porphyria.

Porphyrias are inherited disorders of the heme biosynthetic pathway, usually characterized by dermatological changes due to the accumulation of byproducts in the pathway. Select porphyrias also affect the nervous system, namely hereditary coproporphyria, acute intermittent porphyria and variegate porphyria. Complications include paralysis, hyponatremia which can risk central pontine myelinolysis, seizures and coma. Neurological complications usually result from severe episodes of acute attacks. Acute attacks may also elicit neuropsychiatric symptoms such as confusion, hallucinations, anxiety and psychosis. However, these manifestations are generally self-limiting. Due to the generally low incidence of porphyria and full knowledge the associated neurological and psychiatric manifestations, we review the relevant porphyrias along with their clinical manifestations, evaluation, and management to raise its awareness in the clinical picture and to prevent misdiagnosis. Porphyria should be considered within the differential diagnosis for unexplained neurological symptoms.

Porphyrias: A clinically based approach.

BACKGROUND: Porphyrias are a group of metabolic diseases, individually rare but with an important combined prevalence. Because of their pathological complexity and clinical heterogeneity, they present a challenging diagnosis. The present review aims to provide a clinically based approach to the recognition and treatment of these disorders. METHODS: We carried out a search in PubMed, with the keyword "porphyria", for reviews published in English from 2010 until 2017. RESULTS: The research yielded 196 papers, of which 64 were included in the final narrative review. CONCLUSIONS: Porphyrias can be divided based on clinical presentation in acute neurovisceral, chronic cutaneous bullous, chronic cutaneous non-bullous and acute neurovisceral/chronic cutaneous bullous. Each individual porphyria presents a characteristic pattern of porphyrins in plasma, urine, stool and red blood cells. As such, diagnosis is easily obtained by following a simple diagnostic algorithm. Early recognition is key in managing these diseases. Neurovisceral porphyrias require acute support therapy and chronic eviction of precipitating factors. Cutaneous prophyrias, as photosensitivity disorders, rely on sunlight avoidance and, in some cases, specific therapeutic interventions. Given the rarity of these conditions, physician awareness is crucial.

Clinical Guide and Update on Porphyrias.

Physicians should be aware of porphyrias, which could be responsible for unexplained gastrointestinal, neurologic, or skin disorders. Despite their relative rarity and complexity, most porphyrias can be easily defined and diagnosed. They are caused by well-characterized enzyme defects in the complex heme biosynthetic pathway and are divided into categories of acute vs non-acute or hepatic vs erythropoietic porphyrias. Acute hepatic porphyrias (acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and aminolevulinic acid dehydratase deficient porphyria) manifest in attacks and are characterized by overproduction of porphyrin precursors, producing often serious abdominal, psychiatric, neurologic, or cardiovascular symptoms. Patients with variegate porphyria and hereditary coproporphyria can present with skin photosensitivity. Diagnosis relies on measurement of increased urinary 5-aminolevulinic acid (in patients with aminolevulinic acid dehydratase deficient porphyria) or increased 5-aminolevulinic acid and porphobilinogen (in patients with other acute porphyrias). Management of attacks requires intensive care, strict avoidance of porphyrinogenic drugs and other precipitating factors, caloric support, and often heme therapy. The non-acute porphyrias are porphyria cutanea tarda, erythropoietic protoporphyria, X-linked protoporphyria, and the rare congenital erythropoietic porphyria. They lead to the accumulation of porphyrins that cause skin photosensitivity and occasionally severe liver damage. Secondary elevated urinary or blood porphyrins can occur in patients without porphyria, for example, in liver diseases, or iron deficiency. Increases in porphyrin precursors and porphyrins are also found in patients with lead intoxication. Patients with porphyria cutanea tarda benefit from iron depletion, hydroxychloroquine therapy, and, if applicable, elimination of the hepatitis C virus. An α-melanocyte-stimulating hormone analogue can reduce sunlight sensitivity in patients with erythropoietic protoporphyria or X-linked protoporphyria. Strategies to address dysregulated or dysfunctional steps within the heme biosynthetic pathway are in development.

Murine models of the human porphyrias: Contributions toward understanding disease pathogenesis and the development of new therapies.

Mouse models of the human porphyrias have proven useful for investigations of disease pathogenesis and to facilitate the development of new therapeutic approaches. To date, mouse models have been generated for all major porphyrias, with the exception of X-linked protoporphyria (XLP) and the ultra rare 5-aminolevulinic acid dehydratase deficient porphyria (ADP). Mouse models have been generated for the three autosomal dominant acute hepatic porphyrias, acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). The AIP mice, in particular, provide a useful investigative model as they have been shown to have acute biochemical attacks when induced with the prototypic porphyrinogenic drug, phenobarbital. In addition to providing important insights into the disease pathogenesis of the neurological impairment in AIP, these mice have been valuable for preclinical evaluation of liver-targeted gene therapy and RNAi-mediated approaches. Mice with severe HMBS deficiency, which clinically and biochemically mimic the early-onset homozygous dominant AIP (HD-AIP) patients, have been generated and were used to elucidate the striking phenotypic differences between AIP and HD-AIP. Mice modeling the hepatocutaneous porphyria, porphyria cutanea tarda (PCT), made possible the identification of the iron-dependent inhibitory mechanism of uroporphyrinogen decarboxylase (UROD) that leads to symptomatic PCT. Mouse models for the two autosomal recessive erythropoietic porphyrias, congenital erythropoietic porphyria (CEP) and erythropoeitic protoporphyria (EPP), recapitulate many of the clinical and biochemical features of the severe human diseases and have been particularly useful for evaluation of bone marrow transplantation and hematopoietic stem cell (HSC)-based gene therapy approaches. The EPP mice have also provided valuable insights into the underlying pathogenesis of EPP-induced liver damage and anemia.

[The cutaneous porphyrias]. / Porphyries cutanées.

The porphyrias are a group of metabolic disorders resulting from an innate abnormality in haem biosynthesis, and the clinical settings of which vary according to the genetic enzyme abnormality in question. These are genetic disorders with autosomal dominant or recessive inheritance of varying penetrance, and whose clinical expression differs according to the preferential location of haem precursors. Different classifications have been proposed according to genetic inheritance, the enzyme anomaly at issue, and clinical expression. The clinical classification distinguishes between acute porphyria (acute intermittent porphyria, porphyria variegata, hereditary coproporphyria), bullous cutaneous porphyrias (porphyria cutanea tarda, porphyria variegata and hereditary coproporphyria), painful photosensitive acute cutaneous porphyrias (erythropoietic protoporphyria and X-linked dominant protoporphyria), and rare recessive porphyrias (congenital erythropoietic porphyria, Doss porphyria, hepatoerythropoietic porphyria and harderoporphyria). Treatment depends on the clinical expression of the disorder.

Psicoterapia de constructos personales: intervención centrada en dilemas en un caso de ansiedad generalizada / Psychotherapy of personal constructs: intervention focused on dilemmas in a case of generalized anxiety

Esta presentación de caso, expone una intervención de Constructos Personales centrada en dilemas implicativos en una adolescente de 16 años de la ciudad de Medellín diagnosticada con Porfiria Aguda Intermitente de acuerdo con la Clasificación Internacional de Enfermedades (CIE 10) y con Trastorno De Ansiedad Generalizada (TAG) acorde a los criterios del Manual Diagnóstico y Estadístico de los Trastornos Mentales, quinta edición (DSM 5). El proceso terapéutico se desarrolló en deciseís sesiones, teniendo como punto de referencia los parámetros propuestos por Senra, Feixas y Fernandes (2005), quienes plantean un protocolo general para el abordaje de estructuras dilemáticas, igualmente se consideró la elaboración posterior de Feixas y Compañ (2015) para el diseño del proceso terapéutico. Se definieron los dilemas implicativos a partir de la entrevista, la técnica de rejilla y la autocaracterización (Kelly, 1955). Durante la psicoterapia se abordaron dos de las configuraciones dilemáticas, las cuales se relacionaban con competencia personal e interacción social. En la etapa de finalización del tratamiento se evidenciaron cambios significativos a nivel del sistema de construcciones personales tales como el aumento de la autoestima, mayor percepción de cercanía con las personas significativas, así como una mayor adecuación de éstos a sus construcciones valoradas, transformaciones cuantificadas gracias a la Técnica de Rejilla de Kelly. Igualmente, a nivel sintomático se lograron cambios notables, partiendo de la comparación de las mediciones pre-post tratamiento obtenidas con el inventario de ansiedad y depresión de Beck (BAI, BDI II). Estos resultados aportan evidencia a la Psicología de Constructos Personales, confirmando hallazgos anteriormente expuestos en la literatura científica.

This case presentation exposes an intervention of personal constructs, focused on implicative dilemmas in a 16-year-old girl from Medellin diagnosed with intermittent acute porphyria (AIP) according to the International Classification of Diseases (ICD 10) and with disorder of generalized anxiety (DGA) according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM 5). The therapeutic process was developed in sixteen sessions, having as reference the parameters proposed by Senra, Feixas, and Fernandes (2005), who propose a general protocol for the approach of dilemmatic structures, the subsequent elaboration of Feixas and Compañ was also considered (2015) for the design of the therapeutic process. The implicative dilemmas were defined from the interview, the grid technique and the self-characterization (Kelly, 1955). During psychotherapy, two of the dilemmatic configurations were addressed, which related to personal competence and social interaction. In the stage of completion of the treatment, significant changes were evidenced at the level of the personal construction system such as the increase of self-esteem, greater perception of closeness with significant people, as well as, a greater adaptation of these to their value constructions; quantified transformations thanks to Kelly's Grid Technique. Similarly, significant changes were achieved at the symptomatic level, based on the comparison of pre-post treatment measurements obtained with Beck's anxiety and depression inventory (BAI, BDI II). These results provide evidence to the psychology of personal constructs, which confirms findings previously exposed in the scientific literature.

[Porphyrias-what is verified?] / Porphyrien ­ was ist gesichert?

Porphyrias are caused by enzyme defects of heme biosynthesis. According to their clinical presentation and to each affected pathway, they are categorized into acute and non-acute as well as hepatic and erythropoietic porphyrias. Acute hepatic porphyrias, e.g. acute intermittent porphyria (AIP), porphyria variegata (VP), hereditary coproporphyria (HCP) and 5­aminolevulinic acid dehydratase-deficient porphyria (ALADP) are characterized by accumulation of the porphyrin precursors 5­aminolevulinic acid (ALA) and porphobilinogen (PBG) that correlate with severe abdominal, psychiatric, neurological or cardiovascular symptoms. Additionally, skin photosensitivity can occur in VP and less frequently, in HCP. Decisive for the diagnosis of acute hepatic porphyrias are a >4-fold elevated urinary excretion of ALA in ALADP and ALA and PBG in all other acute porphyrias. First-line treatment of an acute porphyria attack includes intensive care with pain management, sufficient caloric supply, strict avoidance of porphyrinogenic drugs and elimination of other triggering factors. Heme therapy is indispensable in case of developing neurological symptoms and clinical worsening despite first-line measures. Non-acute porphyrias, mainly porphyria cutanea tarda (PCT), erythropoietic protoporphyria (EPP) and X­linked protoporphyria (XLP) display accumulation of porphyrins in the skin and/or liver resulting in photosensitivity up to possible liver damage. Patients with PCT benefit from iron depletion, low-dose chloroquine treatment and/or hepatitis C virus elimination. Afamelanotide is associated with better sunlight tolerance in patients with EPP and XLP. Moreover, innovative therapies that highly selectively address dysregulated steps of the heme biosynthetic pathway are currently under clinical trial.