RESUMO
Background: Acute hepatic porphyrias (AHP) represent a rare group of inherited metabolic disorders of heme biosynthesis pathway. This study aims to determine the diagnostic and prognostic value of serum neurofilament light chain (NfL) as potential biomarker for AHP. Methods: We conducted a cross-sectional observational study to evaluate NfL levels in patients with AHP. They were divided in different groups: normal health individuals; patients with definitive diagnosis of AHP during acute episodes; patients with AHP and infrequent attacks; patients with AHP and recurrent attacks; asymptomatic individuals with positive genetic testing and urinary delta-aminolevulinic acid (ALA) and porphobilinogen (PBG) levels elevated 4 or more times ("high excretors"); asymptomatic individuals with exclusive positive genetic test; control group with Hereditary Amyloidosis related to Transthyretin with Polyneuropathy (ATTRv-PN). Results: During acute attacks, serum NfL levels were 68 times higher compared to normal controls and disclosed a strong correlation with ALA and PBG levels; also exhibited elevated levels in patients with chronic symptoms regardless of the number of disease attacks compared to healthy controls, and at similar levels to patients with ATTRv-PN, which is a model of progressive neuropathy. Conclusion: This study represents the first to establish NfL as a biomarker for AHP, disclosing NfL as a sensitive biomarker for axonal damage and chronic symptom occurrence. This study not only underscores that neurological damage associated with the disease in any patient, irrespective of the number of attacks, but also reinforces the progressive and profoundly debilitating nature of acute and chronic symptoms observed in individuals with AHP.
RESUMO
BACKGROUND: Porphyrias are a rare group of disease due to inherited defects of heme synthesis with important systemic manifestations and great burden of disease for patients and families due to the exceptional course of disease with disabling chronic symptoms interposed by life-threatening acute attacks. Unfortunately, the porphyrias are usually underrecognized reflecting a lack of medical and disease awareness as well as few studies about natural history in large cohorts of patients. The main aim of this article is present consistent data about natural history and burden of disease in a large Brazilian cohort. METHODS: We conducted a national cross-sectional registry with retrospective clinical data of Brazilian patients with porphyria collected with Brazilian patients Association with Porphyria in collaboration with a tertiary care center for rare diseases. RESULTS: A cohort of 172 patients was analyzed in which 148 (86%) patients had the diagnosis of acute hepatic porphyria [AHP] that needed a mean of 62.04 medical visits and 9.6 years to achieve a definitive diagnosis. About AHP cohort, the most common first clinical manifestation were abdominal pain in 77 (52%) patients and acute muscle weakness in 23 (15.5%) with 73 (49.3%) patients presenting only one attack during disease course and 37 (25%) exhibiting 4 or more attacks in the last year. Of note, 105 patients with AHP reported chronic manifestations and the scores for quality of life are lower when compared with general healthy population. CONCLUSIONS: Brazilian patients with AHP had a higher prevalence of chronic disabling manifestations and a poor quality of life like other cohorts and a higher proportion of patients with recurrent attacks than previously reported.
Assuntos
Porfiria Aguda Intermitente , Porfirias , Humanos , Estudos Retrospectivos , Qualidade de Vida , Brasil/epidemiologia , Estudos Transversais , Porfirias/genética , Porfirias/complicações , Porfirias/diagnóstico , Porfiria Aguda Intermitente/genéticaRESUMO
RESUMEN Introducción: Las porfirias hepáticas agudas son un trastorno genético causado por actividad irregular en la síntesis del grupo hemo. Aunque son de baja incidencia, su presencia puede aumentar el riesgo de muerte y afectar la calidad de vida de los pacientes. Se realizó una búsqueda bibliográfica con un intervalo desde el año 2015 al 2020, sobre porfirias hepáticas agudas. Objetivos: Actualizar sobre las alternativas diagnósticas y terapéuticas para las porfirias hepáticas agudas en adultos. Desarrollo: La exposición a ciertos factores precipitantes como fármacos, infecciones y estrés, conllevan a una crisis aguda de porfiria, que desencadenan síntomas neuroviscerales y requiere hospitalización. Existen teorías aisladas que explican el mecanismo de daño durante el ataque agudo, como la hiperactividad autónoma, inflamación, disfunción endotelial, mitocondrial, lesión renal y neurotoxicidad. Sin embargo, el reconocimiento clínico de estos mecanismos sin un diagnóstico conocido de porfiria es un reto para el personal médico, debido a la presencia de síntomas y signos inespecíficos, lo que retrasa el diagnóstico. Debido a la dependencia de la hemina de por vida, se han optado por nuevas alternativas terapéuticas como la supresión genética y el trasplante hepático. El pronóstico es favorable cuando se realiza el diagnóstico a tiempo. Conclusiones: Las alternativas diagnósticas y terapéuticas para las porfirias hepáticas agudas en adultos han evolucionado hacia el trasplante ortotópico hepático y la terapia génica, la cual se ha convertido en un enfoque terapéutico prometedor y validado para el tratamiento de los pacientes con porfirias hepáticas.
ABSTRACT Introduction: Acute hepatic porphyria is a genetic disorder caused by irregular activity in the synthesis of the heme group. Although they are of low incidence, their presence can increase the risk of death and affect the quality of life of patients. A bibliographic search was carried out with a time interval from 2015 to 2020 on acute hepatic porphyria. Objectives: To update on the diagnostic and therapeutic alternatives for acute hepatic porphyria in adults. Development: Exposure to certain precipitating factors such as drugs, infections, and stress leads to an acute porphyria crisis, which triggers neurovisceral symptoms and requires hospitalization. There are isolated theories that explain the mechanism of damage during the acute attack, such as autonomic hyperactivity, inflammation, endothelial and mitochondrial dysfunction, kidney damage, and neurotoxicity. However, clinical recognition of these mechanisms without a known diagnosis of porphyria is challenging for medical personnel, due to the presence of nonspecific symptoms and signs, delaying diagnosis. Due to the dependence on hemin for life, new therapeutic alternatives such as gene suppression and liver transplantation have been chosen. The prognosis is favorable when the diagnosis is made in time. Conclusion: Diagnostic and therapeutic alternatives for acute hepatic porphyria in adults have evolved towards orthopedic liver transplantation and gene therapy, which has become a promising and validated therapeutic approach for the treatment of patients with hepatic porphyria.
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Acute hepatic porphyria represents a rare, underdiagnosed group of inherited metabolic disorders due to hereditary defects of heme group biosynthesis pathway. Most patients have their definite diagnosis after several years of complex and disabling clinical manifestations and commonly after life-threatening acute neurovisceral episodes or severe motor handicap. Many key studies in the last two decades have been performed and led to the discovery of novel possible diagnostic and prognostic biomarkers and to the development of new therapeutic purposes, including small interfering RNA-based therapy, specifically driven to inhibit selectively delta-aminolevulinic acid synthase production and decrease the recurrence number of severe acute presentation for most patients. Several distinct mechanisms have been identified to contribute to the several neuromuscular signs and symptoms. This review article aims to present the current knowledge regarding the main pathophysiological mechanisms involved with the acute and chronic presentation of acute hepatic porphyria and to highlight the relevance of such content for clinical practice and in decision making about therapeutic options.