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In recent years, significant progress has been made in 5q Spinal Muscular Atrophy therapeutics, emphasizing the importance of early diagnosis and intervention for better clinical outcomes. Characterized by spinal cord motor neuron degeneration, 5q-SMA leads to muscle weakness, swallowing difficulties, respiratory insufficiency, and skeletal deformities. Recognizing the pre-symptomatic phases supported by screening and confirmatory genetic tests is crucial for early diagnosis. This work addresses key considerations in implementing 5q-SMA screening within the Brazilian National Newborn Screening Program and explores Brazil's unique challenges and opportunities, including genetic tests, time-to-patient referral to specialized centers, program follow-up, and treatment algorithms. We aim to guide healthcare professionals and policymakers, facilitating global discussions, including Latin American countries, and knowledge-sharing on this critical subject to improve the care for newborns identified with 5q SMA.

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INTRODUCTION: The high prevalence of endogamy, or inbreeding, in northeastern Brazil, is due to historical and cultural factors, with large families living in cities far from the coast and subject to low socioeconomic and infrastructure levels. This breeding practice results in low genetic variability with an increased prevalence of rare autosomal recessive and neurodegenerative diseases, such as spinal muscular atrophy (SMA). OBJECTIVE: Understanding the impact of communicating the diagnosis of SMA on the mental health of patients and their families and the differences between the Northeast (endogamous region) and the other regions of Brazil (non-endogamous ones). METHODS: Cross-sectional study obtained through a structured questionnaire about the moment of receiving the SMA diagnosis, containing the Impact of Event Scale-Revised. RESULTS AND DISCUSSION: The sample consisted of 100 volunteers from all regions of Brazil, 47 patients diagnosed with SMA and 53 family members present at the time of the diagnosis. There was a predominance of females (83%) and homogeneity between the groups for the variables gender, age, color, education, religion, and SMA subtype (1, 2, 3, and 4). The Northeast region, representing 43% of the sample, despite being less economically favored, showed greater satisfaction with medical care and inclusion in health services, with less self-reported psychological trauma and fewer signs of post-traumatic stress disorder (PTSD) related to the moment of receiving the diagnosis. The non-endogamous regions, in turn, reported the presence of strong waves of emotion, sleep problems, feelings of irritability, anger, and the presence of bad thoughts related to this situation. CONCLUSION: The feeling of inclusion in health services and satisfaction with medical care in the endogamous region had a positive impact on the mental health of those involved, reducing psychological trauma and signs of PTSD arising from the communication of the SMA diagnosis.

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La atrofia muscular espinal (AME) 5q es una de las enfermedades neuromusculares de mayor incidencia en la infancia. Sin embargo, la prevalencia de AME tipo 1, su forma más severa de presentación, es menor debido a muertes prematuras evitables antes de los dos años por insuficiencia ventilatoria subtratada. La irrupción de nuevos tratamientos modificadores de la enfermedad pueden cambiar dramáticamente este pronóstico y es una oportunidad para actualizar el manejo respiratorio, a través de cuidados estandarizados básicos, preferentemente no invasivos, abordando la debilidad de los músculos respiratorios, la insuficiencia tusígena y ventilatoria, con un enfoque preventivo. La siguiente revisión literaria entrega estrategias para evitar la intubación y la traqueostomía usando soporte ventilatorio no invasivo (SVN), reclutamiento de volumen pulmonar (RVP) y facilitación de la tos. Se analizan en detalle los protocolos de extubación en niños con AME tipo 1.

Spinal muscular atrophy (SMA) 5q is one of the neuromuscular diseases with the highest incidence in childhood. Nevertheless, the prevalence of its most severe form SMA1 is lower due to premature preventable deaths before two years of age related to ventilatory insufficiency undertreated. The emergence of new disease-modifying treatments can dramatically change this prognosis and is an opportunity to update respiratory management, through basic standardized care, mostly non-invasive, addressing respiratory muscles pump weakness, cough and ventilatory insufficiency with a preventive approach. This literature review provides consensus recommendations for strategies to avoid intubation and tracheostomy using noninvasive ventilatory support (NVS), lung volume recruitment (LVR), and cough facilitation. Extubation protocols in children with SMA type 1 are analyzed in detail.

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The identification of biomarkers for spinal muscular atrophy is crucial for predicting disease progression, severity, and response to new disease-modifying therapies. This study aimed to investigate the role of serum levels of myostatin and follistatin as biomarkers for spinal muscular atrophy, considering muscle atrophy secondary to denervation as the main clinical manifestation of the disease. The study evaluated the differential gene expression of myostatin and follistatin in a lesional model of gastrocnemius denervation in mice, as well as in a meta-analysis of three datasets in transgenic mice models of spinal muscular atrophy, and in two studies involving humans with spinal muscular atrophy. Subsequently, a case-control study involving 27 spinal muscular atrophy patients and 27 controls was conducted, followed by a 12-month cohort study with 25 spinal muscular atrophy cases. Serum levels of myostatin and follistatin were analysed using enzyme-linked immunosorbent assay at a single centre in southern Brazil. Skeletal muscle gene expression of myostatin decreased and of follistatin increased following lesional muscle denervation in mice, consistent with findings in the spinal muscular atrophy transgenic mice meta-analysis and in the iliopsoas muscle of five patients with spinal muscular atrophy type 1. Median serum myostatin levels were significantly lower in spinal muscular atrophy patients (98 pg/mL; 5-157) compared to controls (412 pg/mL; 299-730) (P < 0.001). Lower myostatin levels were associated with greater disease severity based on clinician-rated outcomes (Rho = 0.493-0.812; P < 0.05). After 12 months, there was a further reduction in myostatin levels among spinal muscular atrophy cases (P = 0.021). Follistatin levels did not differ between cases and controls, and no significant changes were observed over time. The follistatin:myostatin ratio was significantly increased in spinal muscular atrophy subjects and inversely correlated with motor severity. Serum myostatin levels show promise as a novel biomarker for evaluating the severity and progression of spinal muscular atrophy. The decrease in myostatin levels and the subsequent favourable environment for muscle growth may be attributed to denervation caused by motor neuron dysfunction.

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La atrofia muscular espinal (AME) de presentación temprana representa la variante más severa, con una expectativa de vida generalmente no mayor a dos años sin soporte ventilatorio, debido a la insuficiencia respiratoria y la dificultad para toser. Tradicionalmente, el manejo respiratorio en muchos países ha incluido la traqueostomía para proporcionar asistencia ventilatoria invasiva de manera continua. No obstante, la introducción de medicamentos de precisión ha modificado la progresión natural de la enfermedad, evidenciando mejoras significativas en los hitos motores y beneficiando también la función respiratoria. A pesar de estas mejoras, en muchos casos sigue siendo necesaria la ventilación intermitente y/o continua, además de la facilitación de la tos. Estas necesidades pueden abordarse de forma no invasiva mediante el soporte ventilatorio no invasivo (SVN), la in-exsuflación mecánica (IEM) y el reclutamiento de volumen pulmonar (RVP), que son considerados pilares del tratamiento respiratorio en enfermedades neuromusculares. Estas estrategias promueven el desarrollo y mantenimiento de la función respiratoria, reduciendo el riesgo de exacerbaciones respiratorias que podrían llevar a intubaciones evitables. Comúnmente, los pacientes con AME experimentan intentos fallidos de extubación siguiendo protocolos tradicionales, siendo catalogados como no extubables y potenciales candidatos a traqueostomía. No obstante, existen protocolos de extubación específicos para AME que emplean SVN e IEM con un alto porcentaje de éxito, evitando traqueostomías innecesarias que pueden complicar la progresión de la enfermedad y afectar la calidad de vida. El enfoque respiratorio no invasivo es una opción de manejo segura tanto en el hospital como en el hogar, ofreciendo una mejor calidad de vida para los pacientes y sus familias.

Early-onset spinal muscular atrophy (SMA) is the most severe variant, with a life expectancy generally not exceeding two years without ventilatory support due to respiratory insufficiency and difficulty in coughing. Traditionally, respiratory management in many countries has included tracheostomy to provide continuous invasive ventilatory support. However, the introduction of precision medicine has altered the natural progression of the disease, showing significant improvements in motor milestones and also benefiting respiratory function. Despite these improvements, many cases still require intermittent and/or continuous ventilation, as well as cough facilitation. These needs can be addressed non-invasively through non-invasive ventilatory support (NIV), mechanical insufflation-exsufflation (MIE), and lung volume recruitment (LVR), which are considered the pillars of respiratory treatment in neuromuscular diseases. These strategies promote the development and maintenance of respiratory function, reducing the risk of respiratory exacerbations that could lead to avoidable intubations. Commonly, SMA patients experience failed extubation attempts following traditional protocols, being labeled as non-extubatable and potential candidates for tracheostomy. Nevertheless, there are specific extubation protocols for SMA that employ NIV and MIE with a high success rate, avoiding unnecessary tracheostomies that can complicate disease progression and impact quality of life. The non-invasive respiratory approach is a safe management option both in the hospital and at home, offering a better quality of life for patients and their families.

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Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by degeneration of lower motor neurons (LMNs), causing muscle weakness, atrophy, and paralysis. SMA is caused by mutations in the Survival Motor Neuron 1 (SMN1) gene and can be classified into four subgroups, depending on its severity. Even though the genetic component of SMA is well known, the precise mechanisms underlying its pathophysiology remain elusive. Thus far, there are three FDA-approved drugs for treating SMA. While these treatments have shown promising results, their costs are extremely high and unaffordable for most patients. Thus, more efforts are needed in order to identify novel therapeutic targets. In this context, zebrafish (Danio rerio) stands out as an ideal animal model for investigating neurodegenerative diseases like SMA. Its well-defined motor neuron circuits and straightforward neuromuscular structure offer distinct advantages. The zebrafish's suitability arises from its low-cost genetic manipulation and optical transparency exhibited during larval stages, which facilitates in vivo microscopy. This review explores advancements in SMA research over the past two decades, beginning with the creation of the first zebrafish model. Our review focuses on the findings using different SMA zebrafish models generated to date, including potential therapeutic targets such as U snRNPs, Etv5b, PLS3, CORO1C, Pgrn, Cpg15, Uba1, Necdin, and Pgk1, among others. Lastly, we conclude our review by emphasizing the future perspectives in the field, namely exploiting zebrafish capacity for high-throughput screening. Zebrafish, with its unique attributes, proves to be an ideal model for studying motor neuron diseases and unraveling the complexity of neuromuscular defects.

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Heterozygous carriers of the survival of motor neuron 1 (SMN1) gene deletion in parents account for approximately 95% of neonatal spinal muscular atrophy cases. Given the severity of the disease, professional organizations have recommended periconceptional spinal muscular atrophy carrier screening to all couples, regardless of race or ethnicity. However, the prevalence of screening activities in mainland China remains suboptimal, mainly attributed to the limitations of the existing carrier screening methods. Herein, we aimed to develop a low-cost, accessible, and accurate carrier screening method based on duplex droplet digital PCR (ddPCR), to cover a wider population in developing countries, including China. The receiver operating characteristic curve was used to determine the cut-off value of SMN1 copy numbers. Performance validation was conducted for linearity, precision, and accuracy. In total, 482 cases were considered to validate the concordance between the developed ddPCR assay and multiplex ligation-dependent probe amplification. Linear correlations were excellent between the expected concentration of the reference gene and the observed values (R2 > 0.99). Both the intra- and inter-assay precision of our ddPCR assays were less than 6.0%. The multiplex ligation-dependent probe amplification and ddPCR results were consistent in 480 of the 482 cases (99.6%). Two cases with multiplex ligation-dependent probe amplification, suggestive of two copies of SMN1 exon 7, were classified into three copies by ddPCR analysis. The overall correct classification of the samples included in our ddPCR assay was 100%. This study demonstrates that an appropriate cut-off value is an important prerequisite for establishing a semi-quantitative method to determine the SMN1 copy numbers. Compared to conventional methods, our ddPCR assay is low-cost, highly accurate, and has full potential for application in population spinal muscular atrophy carriers screening.

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OBJECTIVES: This study aimed to evaluate the cost-effectiveness of the onasemnogene abeparvovec in relation to nusinersen and risdiplam in the treatment of spinal muscular atrophy type 1 from the perspective of the Brazilian Unified Health System. METHODS: A Markov model was built on a lifetime horizon. Short-term data were obtained from clinical trials of the technologies and from published cohort survival curves (long term). Costs were measured in current 2022 local currency (R$) values and benefits in quality-adjusted life-years (QALYs). Utility values were derived from type 1 spinal muscular atrophy literature, whereas costs related to technologies and maintenance care in each health state were obtained from official sources of reimbursement in Brazil. Deterministic and probabilistic, as well as scenario, sensitivity analyses were performed. RESULTS: Compared with the less costly strategy (nusinersen), the use of onasemnogene abeparvovec resulted in an incremental cost of R$2.468.448,06 ($975 671.169 - purchasing power parity [PPP]) and a 3-QALY increment and incremental cost-effectiveness ratio of R$742.890,92 ($293 632.774 - PPP)/QALY. Risdiplam had an extended dominance from other strategies, resulting in an incremental cost-effectiveness ratio of R$926.586,22 ($366 239.612 - PPP)/QALY compared with nusinersen. Sensitivity analysis showed a significant impact of the follow-up time of the cohort and the cost of acquiring onasemnogene abeparvovec. CONCLUSIONS: Over a lifetime horizon, onasemnogene abeparvovec seems to be a potentially more effective option than nusinersen and risdiplam, albeit with an incremental cost. Such a trade-off should be weighed in efficiency criteria during decision making and outcome monitoring from the perspective of the Brazilian Unified Health System.

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PURPOSE: Assistive technologies based on IoT can contribute to improve quality of living of patients with severe motor difficulties by providing partial or total independence. The aim of this work was to analyse the usability and performance of an assistive system based on the IoT when is evaluated by a child patient with spinal muscular atrophy type 1 (SMA-I). MATERIALS AND METHODS: The study involved a child with SMA-I and his caregiver. The materials used include an M5Stack Core2 kit, a mobile app, and a smart switch based on the ESP-01S card. The patient sends requests to the caregiver from the app installed on the M5Stack Core2 to a mobile app, and controls smart switches located in the rooms. The system was tested by the participants for a period of 30 days to later evaluate its usability and performance. RESULTS: The results show that the control function of smart switches is the most used and there is no decrease in interactions over the days for the system in general. In addition, the scores obtained from both usability tests (patient and caregiver) were 87.5% and 90%, respectively. The average performance of the entire system was 93.33%. CONCLUSION: The application of assistive technologies based on the IoT allows obtaining a practical solution that improves the development of daily activities in a patient with SMA-I.

A low-cost device can contribute to improve the quality of living of spinal muscular atrophy patients by favouring partial or total independence.IoT-based assistive technologies allow obtaining practical solutions that improve the development of daily activities.

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Abstract Spinal muscular atrophy linked to chromosome 5 (SMA-5q) is an autosomal recessive genetic disease caused by mutations in the SMN1. SMA-5q is characterized by progressive degeneration of the spinal cord and bulbar motor neurons, causing severe motor and respiratory impairment with reduced survival, especially in its more severe clinical forms. In recent years, highly effective disease-modifying therapies have emerged, either acting by regulating the splicing of exon 7 of the SMN2 gene or adding a copy of the SMN1 gene through gene therapy, providing a drastic change in the natural history of the disease. In this way, developing therapeutic guides and expert consensus becomes essential to direct the use of these therapies in clinical practice. This consensus, prepared by Brazilian experts, aimed to review the main available disease-modifying therapies, critically analyze the results of clinical studies, and provide recommendations for their use in clinical practice for patients with SMA-5q. This consensus also addresses aspects related to diagnosis, genetic counseling, and follow-up of patients under drug treatment. Thus, this consensus provides valuable information regarding the current management of SMA-5q, helping therapeutic decisions in clinical practice and promoting additional gains in outcomes.

Resumo Atrofia muscular espinhal ligada ao cromossomo 5 (AME-5q) é uma doença genética de herança autossômica recessiva causada por mutações no gene SMN1. A AME-5q cursa com degeneração progressiva dos motoneurônios medulares e bulbares, acarretando grave comprometimento motor e respiratório com redução da sobrevida, especialmente nas suas formas clínicas mais graves. Nos últimos anos, terapias modificadoras da doença altamente eficazes, ou que atuam regulando o splicing do exon 7 do gene SMN2 ou adicionando uma cópia do gene SMN1 via terapia gênica, têm surgido, proporcionando uma mudança drástica na história natural da doença. Dessa forma, o desenvolvimento de guias terapêuticos e de consensos de especialistas torna-se importante no sentido de direcionar o uso dessas terapias na prática clínica. Este consenso, preparado por especialistas brasileiros, teve como objetivos revisar as principais terapias modificadoras de doença disponíveis, analisar criticamente os resultados dos estudos clínicos dessas terapias e prover recomendações para seu uso na prática clínica para pacientes com AME-5q. Aspectos relativos ao diagnóstico, aconselhamento genético e seguimento dos pacientes em uso das terapias também são abordados nesse consenso. Assim, esse consenso promove valiosas informações a respeito do manejo atual da AME-5q auxiliando decisões terapêuticas na prática clínica e promovendo ganhos adicionais nos desfechos finais.

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ABSTRACT OBJECTIVE To investigate the costs and profile of patients who have filed a lawsuit against the Ministry of Health for the treatment of spinal muscular atrophy (SMA) with the onasemnogene abeparvovec (Zolgensma®). METHODS This is a cross-sectional, descriptive study with a census design, based on records of lawsuits filed against the Ministry of Health between January 2019 and September 2022. Data was requested from the Ministry of Health via the Access to Information Act. Information was extracted on the epidemiological profile of the beneficiaries of the lawsuits, as well as the expenses spent by the Ministry of Health in cases where the requests were granted. RESULTS 136 lawsuits were identified, of which 113 (83%) were favorable to patients at a cost of R$ 944.8 million in the period analyzed. Demographic (gender and age), clinical (SMA subtypes, use of ventilatory or nutritional support), and lawsuit (type of legal service) characteristics were not associated with the granting of lawsuits. Prior use of medication (nusinersena or ridisplam) was associated with the dismissal of lawsuits. Of the 113 lawsuits granted in favor of patients, only six (5.3%) would meet the criteria currently established by the National Committee for Health Technology Incorporation - Conitec (children up to six months without ventilatory and nutritional support). R$ 146 million was spent on supplying Zolgensma to children over the age of two, which is outside the recommendation contained in the drug's package leaflet. CONCLUSIONS The Ministry of Health incurs a high cost with the judicialization of Zolgensma for SMA, representing 2.45% of total spending on medicines in the Unified Health System, including spending by the three administrative spheres. Some of the lawsuits have been granted in disagreement with the criteria established by health technology assessment agencies and the drug manufacturer's recommendations.

RESUMO OBJETIVO Investigar os custos e o perfil dos pacientes que demandaram judicialmente o onasemnogene abeparvoveque (Zolgensma®) para o tratamento da atrofia muscular espinhal (AME) no Ministério da Saúde. MÉTODOS Estudo transversal, de natureza descritiva e desenho censitário, com base em registros de ações judiciais movidas contra o Ministério da Saúde no período de janeiro de 2019 a setembro de 2022. Os dados foram solicitados ao Ministério da Saúde, via Lei de Acesso à Informação. Foram extraídas informações sobre o perfil epidemiológico dos beneficiários das ações judiciais, bem como os gastos dispendidos pelo Ministério da Saúde nos casos de deferimento das solicitações. RESULTADOS Foram identificados 136 processos judiciais, dos quais 113 (83%) foram favoráveis aos pacientes ao custo de R$ 944,8 milhões no período analisado. Características demográficas (sexo e idade), clínicas (subtipos da AME, uso de suporte ventilatório ou nutricional) e do processo judicial (tipo de serviço advocatício) não foram associadas com o deferimento das ações judiciais. O uso prévio de medicamento (nusinersena ou ridisplam) foi associado com o indeferimento dos processos judiciais. Das 113 ações judiciais concedidas em favor dos pacientes, apenas seis (5,3%) atenderiam aos critérios estabelecidos atualmente pela Comissão Nacional de Incorporação de Tecnologias - Conitec (crianças com até seis meses sem suporte ventilatório e nutricional). Houve dispêndio de R$ 146 milhões com o fornecimento do Zolgensma para crianças com idade superior a dois anos, que está fora da recomendação contida na bula do medicamento. CONCLUSÕES O Ministério da Saúde incorre em um alto custo com a judicialização do Zolgensma para AME, representando 2,45% do gasto total com medicamentos no Sistema Único de Saúde, incluindo gastos das três esferas administrativas. Parte das demandas judiciais tem sido deferida em divergência com os critérios estabelecidos por agências de avaliação de tecnologias em saúde e recomendações do fabricante do medicamento.

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Late-onset spinal muscular atrophy associated with the VAPB gene is a slowly progressing, adult-onset, lower motor neuron disease with an autosomal dominant inheritance pattern. We present a male with progressive weakness beginning at age 44, predominantly in the proximal legs, fasciculations, and gait disturbance, with similar clinical syndrome in his mother. On physical examination, he presented weakness in 4 extremities, predominantly proximal, with atrophy and areflexia. The genetic study identified the c.166C > T mutation in the VAPB gene. The P56S mutation of the VAPB gene is associated with adult-onset spinal muscular atrophy and amyotrophic lateral sclerosis; It has been reported in different countries, although the prevalence is higher in Brazil, related to Portuguese migration. Clinically, the patients present with late-onset ALS or SMA. The disease usually onset in the fifth decade of life as progressive weakness, predominantly proximal in the lower extremities, without bulbar or respiratory involvement.

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OBJECTIVE: This article estimates the disease burden of 5q-SMA in Colombia by using the disability-adjusted life years (DALYs) metric. METHODS: Epidemiological data were obtained from local databases and medical literature and were adjusted in the DisMod II tool. DALYs were obtained by adding years of life lost due to premature death (YLL) and years lived with disability (YLD). RESULTS: The modeled prevalence of 5q-SMA in Colombia was 0.74 per 100,000 population. The fatality rate for all types was 14.1%. The disease burden of 5q-SMA was estimated at 4,421 DALYs (8.6 DALYs/100,000), corresponding to 4,214 (95.3%) YLLs and 207 (4.7%) YLDs. Most of the DALYs were accounted in the 2-17 age group. Of the total burden, 78% correspond to SMA type 1, 18% to type 2, and 4% to type 3. CONCLUSIONS: Although 5q-SMA is a rare disease, it is linked to a significant disease burden due to premature mortality and severe sequelae. The estimates shown in this article are important inputs to inform public policy decisions on how to ensure adequate health service provision for patients with 5q-SMA.

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Introducción. Con las nuevas terapias, el diagnóstico temprano de la atrofia muscular espinal (AME) es esencial. El objetivo de este estudio es analizar los distintos componentes que influyen en el retraso diagnóstico. Población y métodos. Se incluyeron pacientes con un diagnóstico molecular de AME tipo I, II y III. Se estudiaron varios parámetros, como la edad al momento de la aparición del primer signo, qué signo fue y el intervalo entre este y el diagnóstico confirmado. Neurólogos especialistas realizaron entrevistas que se complementaron con la revisión de historias clínicas cuando fue necesario. Resultados. Se entrevistaron 112 pacientes. AME I n = 40, AME II n = 48, AME III n = 24. La mediana de edad en meses al momento del reporte del primer signo fue AME I: 1,5 (R 0-7), AME II: 9 (R 2-20), AME III: 18 (R 8-180). Los primeros signos fueron reconocidos por los padres en el 75 % al 85 % de las veces en todos los subtipos. La mediana del tiempo transcurrido entre el primer signo y la primera consulta médica fue menor a un mes en los tres tipos. La mediana de tiempo transcurrido en meses entre el primer signo y el diagnóstico molecular confirmado fue en AME I: 2 (R 0-11), en AME II: 10 (3-46) y en AME III: 31,5 (R 4-288). Conclusiones. Existe un significativo retraso en el diagnóstico de la AME relacionado fundamentalmente a la falta de sospecha clínica. La demora es menor en AME I y mayor en AME III. Otros factores incluyen deficiencias en el sistema de salud.

Introduction. News treatments, make early diagnosis of spinal muscular atrophy (SMA) critical. The objective of this study is to analyze the different factors that influence delay in diagnosis. Population and methods. Patients with a molecular diagnosis of types I, II, and III SMA were included. Several parameters were studied, such as age at onset of first sign, what sign it was, and the time from recognition of first sign to confirmed diagnosis. Neurologists specialized in SMA conducted interviews, supported by the review of medical records when deemed necessary. Results. A total of 112 patients were interviewed. SMA I n = 40, SMA II n = 48, SMA III n = 24. The median age in months at the time of reporting the first sign was SMA I: 1.5 (R: 0­7), SMA II: 9 (R: 2­20), SMA III: 18 (R: 8­180). In all subtypes, first signs were identified by parents from 75% to 85% of the times. The median time from first sign to first medical consultation was less than a month in all 3 types. The median time in months, from first sign to confirmed molecular diagnosis in SMA I was: 2 (R: 0­11), in SMA II: 10 (R: 3­46), in SMA III: 31.5 (R: 4­288). Conclusions. There is a significant delay in SMA diagnosis mainly related to the absence of clinical suspicion. The delay is shorter in SMA I and longer in SMA III. Other factors include deficiencies in the health care system.

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Introduction. News treatments, make early diagnosis of spinal muscular atrophy (SMA) critical. The objective of this study is to analyze the different factors that influence delay in diagnosis. Population and methods. Patients with a molecular diagnosis of types I, II, and III SMA were included. Several parameters were studied, such as age at onset of first sign, what sign it was, and the time from recognition of first sign to confirmed diagnosis. Neurologists specialized in SMA conducted interviews, supported by the review of medical records when deemed necessary. Results. A total of 112 patients were interviewed. SMA I n = 40, SMA II n = 48, SMA III n = 24. The median age in months at the time of reporting the first sign was SMA I: 1.5 (R: 0-7), SMA II: 9 (R: 2-20), SMA III: 18 (R: 8-180). In all subtypes, first signs were identified by parents from 75% to 85% of the times. The median time from first sign to first medical consultation was less than a month in all 3 types. The median time in months, from first sign to confirmed molecular diagnosis in SMA I was: 2 (R: 0-11), in SMA II: 10 (R: 3-46), in SMA III: 31.5 (R: 4-288). Conclusions. There is a significant delay in SMA diagnosis mainly related to the absence of clinical suspicion. The delay is shorter in SMA I and longer in SMA III. Other factors include deficiencies in the health care system.

Introducción. Con las nuevas terapias, el diagnóstico temprano de la atrofia muscular espinal (AME) es esencial. El objetivo de este estudio es analizar los distintos componentes que influyen en el retraso diagnóstico. Población y métodos. Se incluyeron pacientes con un diagnóstico molecular de AME tipo I, II y III. Se estudiaron varios parámetros, como la edad al momento de la aparición del primer signo, qué signo fue y el intervalo entre este y el diagnóstico confirmado. Neurólogos especialistas realizaron entrevistas que se complementaron con la revisión de historias clínicas cuando fue necesario. Resultados. Se entrevistaron 112 pacientes. AME I n = 40, AME II n = 48, AME III n = 24. La mediana de edad en meses al momento del reporte del primer signo fue AME I: 1,5 (R 0-7), AME II: 9 (R 2-20), AME III: 18 (R 8-180). Los primeros signos fueron reconocidos por los padres en el 75 % al 85 % de las veces en todos los subtipos. La mediana del tiempo transcurrido entre el primer signo y la primera consulta médica fue menor a un mes en los tres tipos. La mediana de tiempo transcurrido en meses entre el primer signo y el diagnóstico molecular confirmado fue en AME I: 2 (R 0-11), en AME II: 10 (346) y en AME III: 31,5 (R 4-288). Conclusiones. Existe un significativo retraso en el diagnóstico de la AME relacionado fundamentalmente a la falta de sospecha clínica. La demora es menor en AME I y mayor en AME III. Otros factores incluyen deficiencias en el sistema de salud.

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Muscle tissue is formed by elongated and contractile cells with specific morphofunctional characteristics. Thus, it is divided into three basic types: smooth muscle tissue, cardiac striated muscle tissue and skeletal striated muscle tissue. The striated skeletal muscle tissue presents high plasticity, regeneration and growth capacity due to the presence of satellite cells, quiescent myoblasts that are activated in case of injury to the tissue and originate new muscle fibers when they differentiate. In more severe deficiencies or injuries there is a loss of their regenerative capacity, thus compromising the body's functionality at different levels. Tissue engineering studies the development of biomaterials capable of stimulating the recovery of cellular activity in injured body tissues, as well as the activity of cells with muscle differentiation potential in injury repair. However, the need for three-dimensional re-assembly in a complex organization makes it difficult to mimic this tissue and fully regenerate it for the sake of precise and effective movements. Thus, this article aims to provide a narrative review of tissue engineering strategies applied to the regeneration of skeletal muscle, in a critical evaluation of research, whether aimed at injury or atrophies such as spinal muscular atrophy.

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El síndrome de Down (SD) es la anomalía cromosómica más frecuente entre los recién nacidos vivos. La atrofia muscular espinal (AME), por su parte, es una enfermedad neuromuscular caracterizada por la degeneración progresiva de las motoneuronas del asta anterior de la médula espinal que produce atrofia muscular, debilidad y parálisis. Presentamos el caso de una niña de 6 años con síndrome de Down derivada a nuestro centro para estudio por cuadro de debilidad muscular generalizada de evolución crónica con falta de adquisición de la marcha. Realizamos una revisión bibliográfica enfocándonos en el compromiso neurológico esperable en el síndrome de Down, la evolución de los hitos del desarrollo motor grueso estipulado para este grupo de pacientes y en los hallazgos que deben sugerir la presencia de una enfermedad neuromuscular.

A case of a 6-year-old girl with Down's syndrome is presented. She was referred to our center due to a history of generalized muscle weakness of chronic evolution, associated to her inability to walk. Her mother claimed that the girl's muscle weakness always called her attention as well as the difficulties to the development of motor skills shown by her daughter compared to other children, whether they were healthy or with Down's syndrome. There was information in her medical record and physical exam that strongly suggested the possibility of suffering a neuromuscular disorder. We asked for a molecular study that confirmed the spinal muscular atrophy diagnosis. We carried out a bibliographical revision focusing on the expected neurological impairment in Down's syndrome, the retardation of the gross motor skills development determined for this kind of patients and on the findings that must suggest a neuromuscular disorder.

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Spinal muscular atrophy (SMA) has been known as a clinical entity for 130 yearsis still recognized today as the most severe autosomal recessive neuromuscular disease (5q,13,2) in pediatrics. Until 2015, SMA treatment was limited to ventilatory, nutritional, and physical therapy support. Currently, the existence of genetic treatments: gene modification by inclusion of exon 7 to the SMN2 gene (nusinersen and risdiplam) or insertion of the SMN1 gene through the adeno-associated viral transporter (onasemnogene) have radically modified the clinical evolution of children with SMA,especially if they are treated early. This review details the effects of the 3 treatments currently in use worldwide.

La atrofia muscular espinal (AME) fue descrita hace 130 años como entidad clínica y se reconoce hasta hoy como la enfermedad neuromuscular autosómica recesiva (5 q,13,2) más grave en pediatría. Hasta el año 2015 el tratamiento de la AME se reducía al apoyo ventilatorio, nutricional y de rehabilitación. Actualmente, la existencia de tratamientos genéticos por modificación del gen mediante inclusión del exón 7 al gen SMN2 (nusinersen y risdiplam) o inserción del gen SMN1 través de transportador viral adenoasociado (onasemnogene) han modificado radicalmente la evolución clínica de los niños con AME,especialmente si son tratados en forma precoz. En esta revisión se detalla los efectos de los 3 tratamientos actualmente en uso a nivel mundial.

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Background: Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disorder showing peripheral hypotonia, atrophy, and weakness in the extremities and bulbar muscles. It is caused by the homozygous deletion of the SMN1 gene on chromosome 5q13. Before 2016, there was no treatment to modify the disease, and in that year it was approved nusinersen, the first drug available to treat this disease, whose action mechanism consists in regulating the SMN2 gene to increase the survival motor neuron (SMN) levels. More recently, the gene therapy onasemnogene aberparvovec-xioi (OAX) was approved for patients under two years of age. The human SMN1 gene is delivered intravenously through an adeno-associated viral type 9 vector. Both therapies appear to show significant improvement in motor function without the presence of severe adverse effects. However, it is unclear whether both treatments can be used together. Clinical case: A 24-month-old male patient with a diagnosis of SMA at 18 months of age. First, he was treated with intrathecal nusinersen administration and later with OAX. When assessing the CHOP INTEND and HFSME function scales, the patient showed an increase in the performance of his motor functions. Conclusion: OAX and nusinersen could be considered in sequence therapies in the presence of SMA. However, this therapy is not yet well established and has not been studied in the long term.

Introducción: la atrofia muscular espinal (AME) es un trastorno neuromuscular autosómico recesivo que se presenta con hipotonía periférica, atrofia y debilidad en las extremidades y músculos bulbares. Es causada por la deleción en estado homocigoto del gen SMN1 en el cromosoma 5q13. Antes de 2016, no había tratamiento modificador de la enfermedad y en ese año fue aprobado el nusinersen, el primer medicamento disponible para esta enfermedad, cuyo mecanismo de acción es modular el gen SMN2 para producir mayor cantidad de proteína de supervivencia de la motoneurona (SMN). En 2019 se aprobó el onasemnogene abeparvovec-xioi (OAX), primer fármaco disponible que utiliza terapia génica. Este se puede emplear únicamente en pacientes menores de dos años y consiste en administrar vía intravenosa el gen humano SMN1 mediante un vector viral adenoasociado tipo 9, con lo que se inicia la producción de proteína SMN. Ambas terapias han demostrado mejoría significativa de la función motora y sin presencia de eventos adversos serios. Sin embargo, aún no está claramente establecido si ambas terapias pueden usarse en conjunto. Caso clínico: paciente de sexo masculino de 24 meses de edad con diagnóstico de AME a los 18 meses, el cual fue tratado inicialmente con nusinersen intratecal y posteriormente con OAX. Al evaluar las escalas de función CHOP INTEND y HFSME el paciente presentó un aumento en el desempeño de sus funciones motoras. Conclusión: el OAX y el nusinersen podrían considerarse terapias en secuencia ante la AME. Sin embargo, esta terapia aún no está bien establecida y no se ha estudiado a largo plazo.

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Diagnosis of later-onset spinal muscular atrophy (SMA) can be challenging. This study aimed to evaluate the diagnostic properties of the detection of muscle fasciculations for SMA diagnosis in adolescents and adults with proximal muscle weakness. A cross-sectional diagnostic accuracy study was performed, in which 10 subjects with SMA (5 with type II and 5 with type III) and 9 subjects with genetic muscle diseases were evaluated by physical examination, muscle ultrasound (MUS) and electromyography (EMG). Inter-rater reliability of MUS was higher than physical examination and in a sensitivity analysis of MUS, all SMA subjects and a single patient with genetic muscle disease presented fasciculations in at least 2 different muscle groups, resulting in a sensitivity of 1 (95% CI: 0.69 to 1) and a specificity of 0.89 (95% CI: 0.52 to 1) for SMA diagnosis. Forty-two percent of evaluated subjects did not agree to perform EMG, limiting this method results. Muscle ultrasound presented the best diagnostic accuracy and physical examination combined with MUS seemed to be a good strategy for screening adolescents and adults with proximal muscle weakness for SMA. These results might improve diagnostic guidelines for later-onset SMA, leading to earlier diagnosis, treatment and specific care.

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