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OBJECTIVES@#To study the natural history of spinal muscular atrophy (SMA) in Chongqing and surrounding areas, China, and to provide a clinical basis for comprehensive management and gene modification therapy for SMA.@*METHODS@#A retrospective analysis was performed on the medical data and survival status of 117 children with SMA.@*RESULTS@#Of the 117 children, 62 (53.0%) had type 1 SMA, 45 (38.5%) had type 2 SMA, and 10 (8.5%) had type 3 SMA, with a median age of onset of 2 months, 10 months, and 15 months, respectively. Compared with the children with type 2 SMA or type 3 SMA, the children with type 1 SMA had significantly shorter time to onset, consultation, and confirmed diagnosis (@*CONCLUSIONS@#There are differences in clinical manifestations and survival rates among children with different types of SMA. The children with type 1 SMA have a low survival rate, and those with type 2 SMA may have non-linear regression of motor ability. Early identification and management of SMA should be performed in clinical practice.
Subject(s)
Child , Humans , Infant , Homozygote , Muscular Atrophy, Spinal/genetics , Retrospective Studies , Sequence Deletion , Spinal Muscular Atrophies of Childhood/geneticsABSTRACT
Objective@#To explore the feasibility of high performance liquid chromatography (DHPLC) combined with multiple ligation-dependent probe amplification (MLPA) for the prenatal diagnosis of spinal muscular atrophy (SMA).@*Methods@#Three families who had given birth to children with SMA type I were subjected to prenatal diagnosis. Peripheral blood samples were collected from the three couples, and 10 mL amniotic fluid was taken for each fetus through amniocentesis at 16-24 gestational week. Following DNA extraction, maternal contamination was excluded by STR analysis. Copy numbers of the SMN genes were detected by denaturing high performance liquid chromatography (DHPLC). Relative copy number of SMN1, SMN2 and reference genes was detected with a MLPA P021 assay kit.@*Results@#The three couples were all found to harbor heterozygous deletion of exon 7 of the SMN1 gene by DHPLC. MLPA analysis also suggested that the three couples were all carriers of SMA mutations. The fetus of family 1 harbored homozygous deletion of exons 7 and 8 of the SMN1 gene, in addition with heterozygous deletion of exons 7 and 8 of the SMN2 gene, suggesting that the fetus had SMA. The fetus of family 2 also harbored homozygous deletion of exons 7 and 8 of the SMN1 gene, while the copy number of SMN2 gene was normal, suggesting that the fetus was a SMA patient too. The fetus of family 3 harbored heterozygous deletion of exons 7 and 8 of the SMN1 gene, in addition with heterozygous deletion of exons 7 and 8 of the SMN2 gene, suggesting that the fetus was a carrier.@*Conclusion@#DHPLC can effectively screen carriers of SMA mutations. Combined DHPLC and MLPA can provide accurate diagnosis for fetuses with a high risk for SMA.
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@#BACKGROUND. Spinal muscular atrophy (SMA MIM#253300) is a heterogeneous group of neuromuscular disorders caused by degeneration of anterior horn cells. Spinal muscular atrophy is the second most common autosomal recessive disorder. The first substantive descriptions of SMA occurred at the end of the 19th century when Werdnig and Hoffman characterized the features of autosomal recessive SMA. SMA is broadly classified into four major categories characterized by the age of onset as well as severity of the disease. Clinically proximal weakness, predominantly athropy, upper muscle athropy and other muscle weakness including of facial, scapula and respiratory were reported. SMA is inherited by X chromosomal, autosomal recessive and dominant mode. In our study, we recruited an individual diagnosed with SMA, without SMN1 gene mutation to investigate BICD2 mutation. Peripherial blood from the patient and his family members were taken to extract genomic DNA according to commercial protocol. Amplification of target gene was done by special primers. DNA sequencing was done to detect a mutation. As a result, we identified a mutation in location c.484 C>T of third exon of BICD2 gene. This mutation is was a heterozygous in mother’ and child’ DNA, SIFT and Polyphen program was used to detect its pathogenic effect. We also checked by Grantham matrix score is 180.0 representing it,s changing acid and alkaline feature in this amino acid. We diagnoses a suspected case with SMA by his clinical symptoms as a SMA type III, Kugelberg-Belander desease. We detected a mutation of BICD2 gene in a patient with SMA. This mutation altered acid and alkaline checked by Grantham matrix. This mutation has never reported before, showing 100% pathogenic effect on protein function, but because of highly penetrate feature of this disease makes its inheritance mode of autosomal dominant pattern.
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Introducción: La atrofia muscular espinal (AME) es una enfermedad degenerativa que afecta las neuronas motoras del asta anterior de la médula espinal, se manifiesta por debilidad muscular progresiva de predominio proximal, hipotonía y arreflexia osteotendinosa, la etiología es una mutación en el gen de supervivencia neuronal SMN. Objetivo: determinar las características clínicas de los pacientes menores de 18 años con atrofia muscular espinal en de Medellín, durante el período 2008-2013. Materiales y métodos: se realizó un estudio descriptivo retrospectivo de los pacientes con AME que consultaron en el Hospital Universitario San Vicente Fundación y un consultorio privado de neuropediatría en Medellín durante el período 2008-2013, en total se recopilaron datos de 29 pacientes, se revisaron las características clínicas, las ayudas diagnósticas practicadas y los tratamientos realizados. Resultados: la AME tipo II resultó la forma clínica más frecuente (62%) seguida por la AME tipo I (24.13%), las principales manifestaciones fueron la hipotonía (100%) debilidad muscular (93.1%) y la arreflexia osteotendinosa (82.8%). Las fasciculaciones en la lengua se presentaron en el 48.3% de los pacientes. La prueba molecular fue realizada en 6 pacientes y en todos se encontró deleción del exón 7 del gen SMN1. Conclusión: la atrofia muscular espinal es una enfermedad degenerativa y de progresión variable de acuerdo a su clasificación. Clínicamente, se debe sospechar cuando exista síndrome motoneuronal y fasciculaciones linguales. El diagnóstico molecular es el método más acertado para confirmar la enfermedad.
Introduction: Spinal muscular atrophy (SMA) is a degenerative disease that affects motor neurons in the anterior horn of the spinal cord, it is manifested by progressive muscle weakness predominantly proximal, hypotonia andosteotendinous arreflexia, the cause is a mutation in neuronal survival gene SMN1 Objective: Establish the clinical, electromyographics and genetics characteristics of patients younger than 18 years with spinal muscular atrophy in the Medellín city, during the period 2008-2013. Materials and methods: A retrospective study of patients with SMA seen in the Hospital Universitario San Vicente Foundation and private center of Neuro- pediatric of Medellín during the period 2008-2013 was performed. Data from 29 patientes were available, were reviewed clinical feature, diagnostic aids and treatments practiced. Results: SMA type II resulted the most frequent clinical presentation (62%) followed by SMA type I (24.13%), the main manifestations were hypotonia (100 %), muscle weakness (93.1%) and osteotendinous arreflexia (82.8%), tongue fasciculations occurred in 48.3% of patients. The molecular test was performed in 6 patients and in all the deletion of exon 7 of the SMN1 gene was found. Conclusion: spinal muscular atrophy is a degenerative and progressive disease according to their clinical classification. It should be suspected when there are motoneuronal syndrome and lingual twitches. Molecular diagnosis is the most accurate to confirm the disease.
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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.