muskeldystrofi

Muskeldystrofi, commonly referred to in English as muscular dystrophy, designates a group of inherited disorders characterized by progressive weakness and degeneration of skeletal muscles. The conditions vary by genetic cause and clinical course but share the feature of gradual loss of muscle function, often with corresponding changes in muscle tissue.

Most forms are caused by mutations in genes that encode components of muscle fibers or their supporting structures. The disorders are heterogeneous and include Duchenne and Becker muscular dystrophy, limb-girdle muscular dystrophies, facioscapulohumeral muscular dystrophy, and myotonic dystrophy, among others. Inheritance can be X-linked, autosomal dominant, or autosomal recessive.

Duchenne and Becker muscular dystrophy result from mutations in the dystrophin gene on the X chromosome and primarily affect boys, though girls can be carriers. Limb-girdle muscular dystrophies affect hip and shoulder girdle muscles and have many genetic subtypes. Myotonic dystrophy involves delayed muscle relaxation and multisystemic features.

Symptoms typically begin with proximal muscle weakness, leading to a waddling gait, difficulty climbing stairs, and frequent falls. Some forms cause early onset wheelchair dependence; others progress more slowly. Cardiac and respiratory complications may occur, and scoliosis or contractures are common.

Diagnosis combines clinical examination, family history, serum creatine kinase levels, muscle imaging, muscle biopsy, and genetic testing to identify the specific mutation. Differential diagnosis includes congenital myopathies and other neuromuscular diseases.

Management is multidisciplinary and supportive. Physical and occupational therapy preserve mobility; orthopedic devices and corrective surgery address contractures and scoliosis. Cardiac and respiratory monitoring are important, with therapies such as corticosteroids used in select Duchenne cases. There is ongoing research into gene therapies and targeted treatments.

Prognosis varies by subtype and severity, ranging from early childhood limitation to late adulthood survival in milder forms. Life expectancy is increasingly improved through advances in care and emerging genetic therapies, but there is currently no cure for most dystrophies.