Distrofia muscular congênita. Parte II: revisão da patogênese e perspectivas terapêuticas

The congenital muscular dystrophies (CMDs) are a group of genetically and clinically heterogeneous hereditary myopathies with preferentially autosomal recessive inheritance, that are characterized by congenital hypotonia, delayed motor development and early onset of progressive muscle weakness associated with dystrophic pattern on muscle biopsy. The clinical course is broadly variable and can comprise the involvement of the brain and eyes. From 1994, a great development in the knowledge of the molecular basis has occurred and the classification of CMDs has to be continuously up dated. In the last number of this journal, we presented the main clinical and diagnostic data concerning the different subtypes of CMD. In this second part of the review, we analyse the main reports from the literature concerning the pathogenesis and the therapeutic perspectives of the most common subtypes of CMD: MDC1A with merosin deficiency, collagen VI related CMDs (Ullrich and Bethlem), CMDs with abnormal glycosylation of alpha-dystroglycan (Fukuyama CMD, Muscle-eye-brain disease, Walker Warburg syndrome, MDC1C, MDC1D), and rigid spine syndrome, another much rare subtype of CMDs not related with the dystrophin/glycoproteins/extracellular matrix complex.As distrofias musculares congênitas (DMCs) são miopatias hereditárias geralmente, porém não exclusivamente, de herança autossômica recessiva, que apresentam grande heterogeneidade genética e clínica. São caracterizadas por hipotonia muscular congênita, atraso do desenvolvimento motor e fraqueza muscular de início precoce associada a padrão distrófico na biópsia muscular. O quadro clínico, de gravidade variável, pode também incluir anormalidades oculares e do sistema nervoso central. A partir de 1994, os conhecimentos sobre genética e biologia molecular das DMCs progrediram rapidamente, sendo a classificação continuamente atualizada. Os aspectos clínicos e diagnósticos dos principais subtipos de DMC foram apresentados no número anterior deste periódico, como primeira parte desta revisão. Nesta segunda parte apresentaremos os principais mecanismos patogênicos e as perspectivas terapêuticas dos subtipos mais comuns de DMC: DMC tipo 1A com deficiência de merosina, DMCs relacionadas com alterações do colágeno VI (Ullrich e Bethlem), e DMCs com anormalidades de glicosilação da alfa-distroglicana (DMC Fukuyama, DMC "Muscle-eye-brain" ou MEB, síndrome de Walker Warburg, DMC tipo 1C, DMC tipo 1D). A DMC com espinha rígida, mais rara e não relacionada com alterações do complexo distrofina-glicoproteínas associadas-matriz extracelular também será abordada quanto aos mesmos aspectos patogênicos e terapêuticos

Floppy infant syndrome due to neuromuscular disorders

A síndrome da criança hipotônica engloba as condições em que a hipotonia muscular se manifesta no recém-nascido ou nos primeiros dois anos de vida. Inclui um grande número de situações que podem ser divididas em dois subtipos: a hipotonia intrínseca ou primária, que depende do acometimento das estruturas que compõem a unidade motora periférica desde o motoneurônio medular até o músculo, e a hipotonia secundária. Esta última ocorre principalmente como sinal acessório em afecções neurológicas com comprometimento do sistema nervoso central, ou no contexto de síndromes genéticas, bem como de doenças sistêmicas graves de caráter extraneurológico. Neste trabalho nos referiremos apenas às situações de hipotonia intrínseca, ou seja, doenças neuromusculares, caracterizando as principais afecções deste grupo no recém-nascido e no lactente, e enfatizando quais os aspectos clínicos que permitem orientar as hipóteses diagnósticas e indicar os exames complementares adequados, principalmente, os testes moleculares, quando possíveis.The congenital hypotonia, also known as the floppy infant syndrome, refers to an infant with generalized hypotonia presenting at birth or in early life. The most important aspect to be considered for assessing the diagnosis is to differentiate between a primary cause of hyptonia due to a neuromuscular disorder and a secondary cause due to non neurological conditions, chromosomal abnormalities or central nervous system involvement (cerebral causes of congenital hypotonia). The focus of the present review are: to report the main neuromuscular disorders, i.e. primary congenital hypotonia, that begin along the first two years of life; to describe the clinical aspects that suggest the differential diagnosis among these entities in order to allowa correct investigation and to avoid unnecessary methods of evaluation. It is also emphasized the value of the molecular diagnosis that is now available for some of these conditions

Distrofia muscular de Duchenne: avaliação da qualidade de vida em 95 pacientes através do Life Satisfaction Index for Adolescents

The purpose of this study was to evaluate the quality of life (QoL) of patients with Duchenne muscular dystrophy (DMD) in different stages of the disease, by means of the Life Satisfaction Index for Adolescents (LSI-A). The practicality of this scale was also verified. The LSI-A was applied four times to 95 patients with DMD who were undergoing steroid therapy, at three-month intervals. The patients were divided into four groups according to age. The results from the four applications and the inter and intra-examiner concordance were treated statistically. Comparing the different age groups, patients with DMD did not lose QoL, even with disease progression. We concluded that, in spite of the progressive course of the disease, the QoL in patients with DMD does not get worse. The use of a scale that embraces a great diversity of circumstances in patients' lives, without considering clinical aspects excessively, is a good alternative for assessing the QoL of these patients.O objetivo deste estudo foi de quantificar a qualidade de vida (QV) em crianças com distrofia muscular de Duchenne (DMD) em diferentes idades através do uso do questionário Life Satisfaction Index for Adolescents (LSI-A). Foi também avaliada a praticidade do questionário. O LSI-A foi aplicado a 95 pacientes com distrofia muscular de Duchenne em corticoterapia, em diferentes idades, e por quatro vezes com intervalos de três meses. Os resultados concernentes às quatro avaliações e a concordância inter e intra-observador foram tratados estatisticamente. Comparando diferentes faixas etárias, mesmo ao longo da progressão da doença, não notamos perda da QV. Concluímos que por não valorizar excessivamente os aspectos clínicos e abranger uma diversidade de circunstâncias cotidianas, O LSI-A é útil na avaliação da QV das crianças com DMD, sendo também de fácil aplicação

Phenotypic and immunohistochemical characterization of sarcoglycanopathies

INTRODUCTION: Limb-girdle muscular dystrophy presents with heterogeneous clinical and molecular features. The primary characteristic of this disorder is proximal muscular weakness with variable age of onset, speed of progression, and intensity of symptoms. Sarcoglycanopathies, which are a subgroup of the limb-girdle muscular dystrophies, are caused by mutations in sarcoglycan genes. Mutations in these genes cause secondary deficiencies in other proteins, due to the instability of the dystrophin-glycoprotein complex. Therefore, determining the etiology of a given sarcoglycanopathy requires costly and occasionally inaccessible molecular methods. OBJECTIVE: The aim of this study was to identify phenotypic differences among limb-girdle muscular dystrophy patients who were grouped according to the immunohistochemical phenotypes for the four sarcoglycans. METHODS: To identify phenotypic differences among patients with different types of sarcoglycanopathies, a questionnaire was used and the muscle strength and range of motion of nine joints in 45 patients recruited from the Department of Neurology - HC-FMUSP (Clinics Hospital of the Faculty of Medicine of the University of São Paulo) were evaluated. The findings obtained from these analyses were compared with the results of the immunohistochemical findings. RESULTS: The patients were divided into the following groups based on the immunohistochemical findings: a-sarcoglycanopathies (16 patients), b-sarcoglycanopathies (1 patient), y-sarcoglycanopathies (5 patients), and nonsarcoglycanopathies (23 patients). The muscle strength analysis revealed significant differences for both upper and lower limb muscles, particularly the shoulder and hip muscles, as expected. No pattern of joint contractures was found among the four groups analyzed, even within the same family. However, a high frequency of tiptoe gait was observed in patients with a-sarcoglycanopathies, while calf pseudo-hypertrophy was most common in patients with non-sarcoglycanopathies. The a-sarcoglycanopathy patients presented with more severe muscle weakness than did y-sarcoglycanopathy patients. CONCLUSION: The clinical differences observed in this study, which were associated with the immunohistochemical findings, may help to prioritize the mutational investigation of sarcoglycan genes.CNP

Contribuição adicional das imagens por tensores de difusão em paralisia do olhar conjugado horizontal associada a escoliose progressiva

In two siblings with clinical diagnosis of horizontal gaze palsy associated with progressive scoliosis (HGPPS) we could demonstrate by diffusion tensor imaging: (1) An anterior displacement of the transverse pontine fibers; (2) Posterior clumping of the corticospinal, medial lemniscus and central tegmental tracts and of the medial and dorsal longitudinal fasciculi complex; (3) Absent decussation of superior cerebellar peduncle. Those findings can contribute as surrogate markers for the diagnosis.Em dois irmãos com diagnóstico clínico de paralisia do olhar conjugado horizontal associada a escoliose progressiva, foi possível determinar através de imagens por tensores de difusão: (1) Deslocamento anterior das fibras pontinas transversas; (2) Agrupamento posterior do trato córtico-espinhal, lemnisco medial e trato tegmentar central e complexos dos fascículos longitudinais medial e dorsal; (3) Ausência da decussação dos pedúnculos cerebelares superiores. Tais achados podem contribuir como marcadores para o diagnóstico

Medida de função motora, corticoterapia e pacientes com distrofia muscular de Duchenne

Objective: To assess the evolution of motor function in patients with Duchenne muscular dystrophy (DMD) treated with steroids (prednisolone or deflazacort) through the Motor Function Measure (MFM), which evaluates three dimensions of motor performance (D1, D2, D3). Methods: Thirty-three patients with DMD (22 ambulant, 6 non-ambulant and 5 who lost the capacity to walk during the period of the study) were assessed using the MFM scale six times over a period of 18 months. Results: All the motor functions remained stable for 14 months in all patients, except D1 for those who lost their walking ability. In ambulant patients, D2 (axial and proximal motor capacities) motor functions improved during six months; an improvement in D3 (distal motor capacity) was noted during the total follow-up. D1 (standing posture and transfers) and total score were useful to predict the loss of the ability to walk. Conclusions: The use of the MFM in DMD patients confirms the benefits of the steroid treatment for slowing the progression of the disease.OBJETIVO: Avaliar a evolução da função motora de pacientes com distrofia muscular de Duchenne (DMD) em corticoterapia (predinisolona e deflazacort), por meio da escala Medida da Função Motora (MFM), que avalia três dimensões de funções motoras (D1, D2, D3). \ud MÉTODOS: Trinta e três pacientes com DMD (22 deambulantes, seis cadeirantes e cinco que perderam a capacidade de andar ao longo do estudo) foram avaliados pela escala MFM em seis momentos durante 18 meses. \ud RESULTADOS: Todas as funções motoras mantiveram-se estáveis durante 14 meses, exceto D1 para os pacientes que perderam a marcha. Nos pacientes deambulantes, a D2 (função motora axial e proximal) apresentou melhora durante seis meses. Melhora em D3 (função motora distal) também foi observada durante o seguimento. A D1 (postura em pé e transferências) e o escore total foram importantes para predizer a perda de marcha. \ud CONCLUSÕES: O uso da MFM nos pacientes com DMD confirma os benefícios do tratamento com corticoides na diminuição da velocidade de progressão da doença

Anti-N-methyl D-aspartate receptor encephalitis in childhood

OBJETIVO: Discutir o diagnóstico diferencial das encefalites além daquelas de etiologia infecciosa, e alertar os pediatras para a possibilidade do diagnóstico de encefalite anti-receptor N-metil-D-aspartato (rNMDA) na população pediátrica, destacando suas principais características clínicas. \ud DESCRIÇÃO: Três pacientes apresentaram-se com uma síndrome neuropsiquiátrica inicial seguida de encefalopatia e transtornos de movimento. As características neuropsiquiátricas iniciais se desenvolveram ao longo de dias ou semanas, com mudanças comportamentais, ansiedade, confusão mental e regressão da fala. Em seguida, os pacientes evoluíram com distúrbios de movimento, caracterizados por coreoatetose ou distonia, acometendo a região orofacial e os membros. Após a exclusão das principais causas de encefalite, foram identificados anticorpos anti-rNMDA no soro e no líquido cefalorraquidiano. Não foram detectadas neoplasias durante a investigação etiológica. Os pacientes foram submetidos a imunossupressão, e dois deles tiveram uma recuperação neurológica completa. Um deles ainda apresenta uma postura distônica leve em um dos membros. \ud COMENTÁRIOS: Os sinais clínicos de encefalite anti-rNMDA em crianças são semelhantes aos anteriormente descritos em adultos. Tumores geralmente não são detectados nessa idade. O diagnóstico de encefalite anti-rNMDA deve ser abordado após a exclusão de outras causas de encefalite na infância, como as de origem infecciosa. Pediatras devem estar atentos a essa condição autoimune passível de tratamento.Objective: To discuss the differential diagnosis of encephalitis beyond that of infectious etiology and to inform pediatricians about the possibility of anti-N-methyl-D-aspartate receptor (NMDAr) encephalitis in children by highlighting its most important clinical features. Description: Three patients presented with an initial neuropsychiatric syndrome followed by encephalopathy and movement disorder. The initial neuropsychiatric features which developed over days to weeks included a change in personality, anxiety, confusion, and speech regression. This was followed by a choreoathetoid or dystonic movement disorder affecting the orofacial region and the limbs. After the exclusion of the major causes of encephalitis, NMDAr antibodies were identified in serum and cerebrospinal fluid, and neoplasm screening did not detect any tumor. Patients were submitted to immunosuppression, and two of them had a full neurological recovery. One of them still presents a mild dystonic posture in a limb. Comments: Clinical signs of anti-NMDAr encephalitis in children are similar to those previously described in adults. Tumors are not usually detected by this age. The diagnosis of anti-NMDAr encephalitis must be addressed only after the exclusion of infectious and other recognizable causes of encephalitis. Pediatricians should be aware of this treatable autoimmune condition

Lung function monitoring in patients with duchenne muscular dystrophy on steroid therapy

Background\ud Duchenne muscular dystrophy (DMD) is a sex-linked inherited muscle disease characterized by a progressive loss in muscle strength and respiratory muscle involvement. After 12 years of age, lung function declines at a rate of 6 % to 10.7 % per year in patients with DMD. Steroid therapy has been proposed to delay the loss of motor function and also the respiratory involvement.\ud \ud Method\ud In 21 patients with DMD aged between seven and 16 years, the forced vital capacity (FVC) and the forced expiratory volume in one second (FEV1) were evaluated at three different times during a period of two years.\ud \ud Results\ud We observed in this period of evaluation the maintenance of the FVC and the FEV1 in this group of patients independently of chronological age, age at onset of steroid therapy, and walking capacity.\ud \ud Conclusion\ud The steroid therapy has the potential to stabilize or delay the loss of lung function in DMD patients even if they are non-ambulant or older than 10 years, and in those in whom the medication was started after 7 years of age.DLM was supported by CAPES (Coordenação de Aperfeiçoamento Pessoal de Ensino Superior)