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Abstract(s)
As distrofias musculares congênitas constituem um grupo heterogêneo de doenças
neuromusculares, com padrão autossômico recessivo, caracterizadas por hipotonia congênita
e fraqueza muscular progressiva, associadas ainda a atraso no desenvolvimento motor e
artrogripose, observado ao nascimento ou nos primeiros meses de vida.
Um dos principais representantes desse grupo é a Distrofia Muscular Congênita com
Deficiência de Merosina, também chamada de laminina a2. A ausência dessa proteína pode
ser completa ou parcial, determinando com isso a severidade do quadro clínico. As
manifestações clínicas incluem o espectro observado em outras formas de distrofia muscular
congênita, embora a maioria dos pacientes com deficiência da merosina apresente intelecto
normal ou limítrofe, com funções mentais preservadas.
Geralmente, esses pacientes apresentam valores elevados de creatina-quinase sérica e
alterações histopatológicas de padrão distrófico em biópsia muscular. Imagens de ressonância
magnética mostram hipodensidade difusa e simétrica na substância branca do cérebro, porém
com preservação de áreas cuja mielinização ocorre durante a gestação, tais como cápsula
interna, corpo caloso ou cerebelo.
O diagnóstico baseia-se no quadro clínico associado a achados laboratoriais e imagiológicos,
sendo confirmado por exame molecular genético, capaz de identificar mutações típicas no
gene LAMA2.
Um dos obstáculos ao diagnóstico precoce é a sintomatologia tardia ou pouco evidente,
particularmente observado nos casos cuja deficiência de merosina é parcial, assim como
ilustra o caso clínico apresentado neste trabalho.
Até o momento, a distrofia muscular congênita com deficiência de merosina não tem cura,
sendo o objetivo terapêutico fundamentado no tratamento das manifestações clínicas e
prevenção de complicações, minimizando com isso o impacto da doença na qualidade de vida
do doente.
Congenital muscular dystrophies are a heterogeneous group of neuromuscular disorders, with autosomal recessive pattern, characterized by congenital hypotonia and progressive muscle weakness, associated with delayed motor development and arthrogryposis observed at birth or in the first few months of life. One of the main representatives of this group is to Congenital Muscular Dystrophy with merosin deficiency, also called Laminin a2. The absence of this protein may be complete or partial, thereby determining the severity of the clinical case. Clinical manifestations include the spectrum observed in other forms of congenital muscular dystrophy, but the majority of patients with merosin deficiency have normal or borderline intellect, with preserved mental functions. Generally, these patients have elevated levels of serum creatine kinase and histopathological changes of dystrophic pattern on muscle biopsy. Magnetic resonance imaging showed diffuse and symmetrical hypodensity in the white matter of the brain, but with preservation of areas which myelination occurs during pregnancy, such as internal capsule, corpus callosum and cerebellum. The diagnosis is based on clinical case associated with laboratory and imaging findings, later confirmed by molecular genetic examination, capable of identifying typical gene mutations in LAMA2. One of the obstacles to early diagnosis is late onset or little obvious symptoms, particularly observed in cases which merosin deficiency is partial, as well as illustrates the case presented in this work. So far, congenital muscular dystrophy with merosin deficiency has no cure, and the therapeutic goal is based on treatment of the clinical manifestations and prevention of complications, thus minimizing the impact of this disease on the patient’s quality of life.
Congenital muscular dystrophies are a heterogeneous group of neuromuscular disorders, with autosomal recessive pattern, characterized by congenital hypotonia and progressive muscle weakness, associated with delayed motor development and arthrogryposis observed at birth or in the first few months of life. One of the main representatives of this group is to Congenital Muscular Dystrophy with merosin deficiency, also called Laminin a2. The absence of this protein may be complete or partial, thereby determining the severity of the clinical case. Clinical manifestations include the spectrum observed in other forms of congenital muscular dystrophy, but the majority of patients with merosin deficiency have normal or borderline intellect, with preserved mental functions. Generally, these patients have elevated levels of serum creatine kinase and histopathological changes of dystrophic pattern on muscle biopsy. Magnetic resonance imaging showed diffuse and symmetrical hypodensity in the white matter of the brain, but with preservation of areas which myelination occurs during pregnancy, such as internal capsule, corpus callosum and cerebellum. The diagnosis is based on clinical case associated with laboratory and imaging findings, later confirmed by molecular genetic examination, capable of identifying typical gene mutations in LAMA2. One of the obstacles to early diagnosis is late onset or little obvious symptoms, particularly observed in cases which merosin deficiency is partial, as well as illustrates the case presented in this work. So far, congenital muscular dystrophy with merosin deficiency has no cure, and the therapeutic goal is based on treatment of the clinical manifestations and prevention of complications, thus minimizing the impact of this disease on the patient’s quality of life.
Description
Keywords
Deficiência de Merosina Distrofia Muscular Congênita Laminina Alfa-2 Merosina Negativa