Cribado neonatal en atrofia muscular espinal: un desafío para cambiar la historia natural / Neonatal screening in spinal muscular atrophy: a challenge to change the natural history

Introducción: la atrofia muscular espinal (AME) es la primera causa de origen genético de muerte en la infancia. En los últimos 20 años han sido excepcionales los avances en el conocimiento de su base genética, de su historia natural y se han desarrollado estándares de cuidado y nuevas terapias. Este veloz aumento del conocimiento ha llevado al desarrollo de terapias eficaces para esta devastadora enfermedad, pero el tiempo son neuronas, y esa frase nos lleva a pensar la importancia del diagnóstico precoz y, por qué no, del diagnóstico presintomático mediante pesquisa neonatal. Métodos: revisión de la bibliografía disponible, a través de búsqueda en PubMed y Google para trabajos no indexados o publicaciones de organismos de Salud. Resultados: varios estudios clínicos han mostrado la mayor eficacia del tratamiento en pacientes presintomáticos, por lo que lograrlo en estos pacientes llevaría a cambiar radicalmente la historia de esta enfermedad. Conclusión: es importante analizar y promover el desarrollo de pilotos para pesquisa neonatal en vistas a lograr experiencia para, a partir de ello, pensar en la posibilidad de incorporarlo a programas nacionales. (AU)

Introduction: spinal muscular atrophy (SMA) is the first cause of genetic origin of death in childhood. Throughout the last 20 years, we have witnessed exceptional advances in the knowledge of its genetic base, the history of its nature and several standards of care and new therapies have been developed. This rapid increase in knowledge has led to the development of effective therapies for this devastating disease. However, time is neurons, and that phrase reminds us of the importance of early diagnosis, and, why not, of pre-symptomatic diagnosis by means of neonatal screening. Methods: review of scientific papers searching in Pubmed or Google for non-indexed articles or publications of Health organisms. Results: several clinical studies have shown the greatest effectiveness of treatment in pre-symptomatic patients, so achieving the same in these patients would result in radically changing the history of this disease. Discussion: it is important to analyze and promote the development of pilots for neonatal screening in order to gain experience, so from there on to be able to think about the possibility of incorporating it into national programs. (AU)

Cuidados respiratorios de los pacientes con atrofia muscular espinal / Respiratory care approach for patients with spinal muscular atrophy

Spinal Muscular Atrophy (SMA) is a disease of the anterior horn of the spinal cord, which causes muscle weakness that leads to a progressive decrease in vital capacity and diminished cough flows. Respiratory morbidity and mortality are a function of the degree of respiratory and bulbar-innervated muscle. The former can be quantitated by the sequential evaluation of vital capacity to determine the lifetime maximum (plateau) and its subsequent rate of decline, progressing to ventilatory failure. SMA types 1 and 2 benefit from non-invasive respiratory care in early childhood and school age, improving quality and life expectancy. This document synthesizes these recommendations with special reference to interventions guided by stages that include air stacking, assisted cough protocols, preparation for spinal arthrodesis and non-invasive ventilatory support, even in those patients with loss of respiratory autonomy, minimizing the risk tracheostomy. Failure to consider these recommendations in the regular assessment of patients reduces the offer of timely treatments.

La Atrofia Muscular Espinal (AME) es una enfermedad genética del asta anterior de la medula espinal, que cursa con debilidad muscular progresiva. La intensidad y precocidad de la debilidad muscular presenta diferentes grados de afectación de los grupos musculares respiratorios, determinando la meseta en la capacidad vital y progresión a la insuficiencia ventilatoria, como también el compromiso de los músculos inervados bulbares. Los AME tipo 1 y 2, se benefician con cuidados respiratorios no invasivos en la infancia temprana y edad escolar, mejorando la calidad y esperanza de vida. Este documento sintetiza dichas recomendaciones, con especial referencia a intervenciones guiadas por etapas, que incluyan apilamiento de aire, protocolos de tos asistida, preparación para la artrodesis de columna y soporte ventilatorio no invasivo, incluso en aquellos pacientes con pérdida de la autonomía respiratoria, minimizando el riesgo de traqueostomía. La no consideración de estas recomendaciones en la valoración regular de los pacientes resta la oferta de tratamientos oportunos.

Sobrecarga del cuidador de pacientes con atrofia muscular espinal / Caregiver burden in spinal muscular atrophy

INTRODUCCIÓN La sobrecarga del cuidador ha sido ampliamente descrita en gerontología, pocos estudios la abordan en niños con enfermedades neuromusculares. El cuidado de pacientes con atrofia muscular espinal (AME), requiere atención continua de un tercero, pudiendo afectar la salud del cuidador y la calidad de atención y bienestar del paciente. El objetivo del estudio fue determinar el nivel de sobrecarga de los cuidadores de pacientes AME, identificando factores protectores y de riesgo asociados MÉTODOS Estudio observacional analítico transversal en padres de pacientes con AME, de un hospital privado de Santiago de Chile. Se analizaron datos demográficos clínicos y encuesta Zarit autoreportada por los padres de los pacientes con AME, realizada entre septiembre de 2017 y febrero de 2018. Se usó estadística descriptiva y regresión logística uni y multivariada para identificar factores asociados a sobrecarga RESULTADOS De los 50 padres encuestados, 14 (28%) eran de pacientes non-sitters, con sobrecarga intensa, mediana de puntaje 59 (37-76), 29 (58%) de pacientes sitters sobrecarga ligera, mediana 48 (32-79) y 7(14%) de pacientes walkers, ausencia de sobrecarga mediana 38 (23-54). Se identificaron como factores protectores de sobrecarga los años de enfermedad OR 0,9 (0,8-0,95) P=0,037 y la mayor edad de los pacientes OR 0,9(08,0,98) p=0,018. Factores de riesgo el uso de silla de ruedas OR 7,2(1,2-4,3) p=0,029 y la vía de alimentación artificial OR 9,2(1-78,8) p=0,040 CONCLUSIÓN Los padres de pacientes con AME tienen un significativo nivel de sobrecarga y existen factores que la aumentan y disminuyen. El equipo multidisciplinario debe integrar la medición periódica del nivel de sobrecarga, para intervenir oportunamente y procurar el cuidado integral de la familia.

Caregiver burden has been widely described in gerontology, few studies address it in children with neuromuscular diseases. The care of patients with spinal muscular atrophy (SMA) requires permanent care from a third person, which may affect the caregiver health, quality of care and well-being of the patient. The aim of the study was to determine the burden of SMA patient's caregivers, identifying associated protective and risk factors METHODS Descriptive cross-sectional analytical study in SMA patient's parents, from a private hospital in Santiago de Chile., demographic Clinical and self-reported Zarit survey data, parents self reported, conducted between September 2017 and February 2018, were analyzed. Descriptive statistics and uni and multivariate logistic regression were used to identify factors associated with overloading RESULTS Parents of non-sitter patients showed a median of 59 (37-76), corresponding to intense burden and those of sitters, a light burden, with a median score of 48 (32-79) Walkers patient's parents, presented a median score of 38 (23-54) that corresponds to an absence of burden. The years of illness and the higher age of the patients were identified as protective factors of overload. As risk factors of burden, the use of a wheelchair and artificial airway. Of the 50 parents surveyed, 14 (28%) were non-sitter patients, with intense overload, median 59(37-76), 29(58%) sitters patients, light overload, median 48 (32-79) and 7(14%) walker patients, absence of overload, median 38 (23-54). Protective factors of overload were years of disease OR 0,9(0,8-0,95) p=0.037 and the patients major age OR 0.9(0.8-0.98) p=0.018. Risk factors were the use of wheelchair OR 7,2(1,2-4,3) p=0.029 and artificial feeding support OR 9,2(1-78.8) p=0.040 CONCLUSION SMA patient's parents have a significant level of overload and there are factors that increase and decrease it. The multidisciplinary team must integrate the periodic measurement of the burden level, to make on time interventions and to ensure the integral care in the family.

Therapeutic advances in 5q-linked spinal muscular atrophy / Avanços terapêuticos na atrofia muscular espinhal ligada ao cromossomo 5q

ABSTRACT Spinal muscular atrophy (SMA) is a severe and clinically-heterogeneous motor neuron disease caused, in most cases, by a homozygous mutation in the SMN1 gene. Regarding the age of onset and motor involvement, at least four distinct clinical phenotypes have been recognized. This clinical variability is, in part, related to the SMN2 copy number. By now, only supportive therapies have been available. However, promising specific therapies are currently being developed based on different mechanisms to increase the level of SMN protein; in particular, intrathecal antisense oligonucleotides that prevent the skipping of exon 7 during SMN2 transcription, and intravenous SMN1 insertion using viral vector. These therapeutic perspectives open a new era in the natural history of the disease. In this review, we intend to discuss the most recent and promising therapeutic strategies, with special consideration to the pathogenesis of the disease and the mechanisms of action of such therapies.

RESUMO A atrofia muscular espinhal (AME) é uma grave doença dos neurônios motores, de grande variabilidade clínica e causada na maioria dos casos por mutação em homozigose no gene SMN1. Pelo menos quatro fenótipos clínicos distintos são reconhecidos com base na idade de início e no grau de envolvimento motor. Tal variabilidade clínica é em parte relacionada com o número de cópias do gene SMN2. Até recentemente, apenas terapias de suporte estavam disponíveis. Atualmente, terapias especificas estão sendo desenvolvidas com base em diferentes mecanismos para aumentar o nível de proteína SMN; em particular oligonucleotídeos antissenso por via intratecal e inserção de cópia do gene SMN1, via endovenosa, usando vetor viral. Nesta revisão, objetivamos discutir as mais recentes e promissoras estratégias terapêuticas, com consideração especial aos aspectos patogênicos da doença e aos mecanismos de ação de tais terapias.

Atrofia muscular espinhal: diagnóstico, tratamento e perspectivas futuras / Spinal muscular atrophy: diagnosis, treatment and future prospects

OBJETIVO: Relatar as recentes descobertas genéticas e moleculares, juntamente com as perspectivas futuras, para o tratamento da atrofia muscular espinhal, auxiliando, dessa forma, os profissionais da área da saúde a fazerem um rápido diagnóstico e proporcionarem um suporte terapêutico correto e precoce. FONTES DOS DADOS: As informações foram coletadas a partir de artigos científicos publicados nas duas últimas décadas, pesquisados nas bases de dados SciELO, PubMed e MEDLINE. SÍNTESE DOS DADOS: A atrofia muscular espinhal é uma doença neurodegenerativa com herança genética autossômica recessiva. É causada por uma deleção homozigótica do gene de sobrevivência do motoneurônio. Essa alteração genética resulta na redução dos níveis da proteína de sobrevivência do motoneurônio, levando à degeneração de motoneurônios alfa da medula espinhal, o que resulta em fraqueza e paralisia muscular proximal progressiva simétrica. Sabe-se que alguns cuidados básicos referentes à nutrição, respiração e fisioterapia podem ser importantes para retardar o progresso da doença e prolongar a vida dos pacientes. Vários medicamentos estão sendo testados, alguns novos, outros já conhecidos, como o ácido valproico, sendo que a paralisia pode ser estacionada, mas não revertida. CONCLUSÕES: A atrofia muscular espinhal é uma desordem de difícil diagnóstico, por ser pouco conhecida, e de tratamento ainda incerto. Os tratamentos farmacológicos e as terapias de suporte existentes ainda não são capazes de recuperar os motoneurônios ou as células musculares que já foram perdidos, mas têm o objetivo de retardar o progresso da doença e melhorar a função muscular residual dos pacientes, bem como oferecer uma melhor qualidade e expectativa de vida.

OBJECTIVE: To report on recent genetic and molecular discoveries and on future prospects for the treatment of spinal muscular atrophy (SMA), thereby helping healthcare professionals to make a quick diagnosis and provide appropriate and timely therapeutic support. SOURCES: Information was collected from scientific articles published in the last 2 decades, retrieved from the databases SciELO, PubMed, and MEDLINE. SUMMARY OF THE FINDINGS: SMA is a neurodegenerative disorder with autosomal recessive genetic heredity. It is caused by a homozygous deletion of the survival motor neuron (SMN1) gene. This genetic alteration results in reduced levels of the SMN protein, leading to degeneration of alpha motor neurons of the spinal cord and resulting in muscle weakness and progressive symmetrical proximal paralysis. It is known that basic nutritional and respiratory care and physiotherapy can be important to delaying disease progression and prolonging patients' lives. Several drugs are being tested, some new, others, such as valproic acid, already known; paralysis can be halted, but not reversed. CONCLUSIONS: SMA is a difficult to diagnose disorder, because it is little known, and treatment is uncertain. Pharmacological treatments and supportive therapies are not yet able to recover motor neurons or muscle cells that have already been lost, but are aimed at delaying disease progression and improving patients' residual muscle function, as well as offering better quality of life and life expectancy.

Aspectos éticos en el manejo de una enfermedad genética / Ethical aspects in the management of a genetic disease

Se describe el caso de un recién nacido con hipotonía y signos que sugerían miopatía congénita tubular. Inicialmente se decidió darle toda clase de apoyo, incluida la eventual conexión a ventilación mecánica, hasta comprobar el diagnóstico mediante una biopsia muscular. Sin embargo, ante su agravación progresiva y la categórica solicitud de sus padres, se decidió no conectar a respirador. El paciente falleció y el resultado de la biopsia, conocido después de la muerte, revelóque sufría de atrofia muscular espinal. Se refelxiona sobre los aspectos éticos comprometidos en este tipo de decisiones, que influyen la autonomía del paciente, los derechos de los padres, los requisitos para decidir abstenciones terapéuticas, los beneficios para el paciente, las condiciones para el consejo genético y las responsabilidades profesionales posteriores con los padres