pediatrics
Congenital Myopathies
Introduction
Congenital myopathyis a term sometimes applied to hundreds of distinct neuromuscular disorders that may be present at birth, but it is usually reserved for a group of rare, inherited, primary muscle disorders that cause hypotonia and weakness at birth or during the neonatal period and, in some cases, delayed motor development later in childhood. Diagnosis is clinical and is confirmed by muscle biopsy and sometimes MRI of the muscles. Treatment is supportive and includes physical therapy. Congenital myopathies are a group of genetic muscle disorders characterized clinically by hypotonia and weakness, usually present from birth, with a static or slowly progressive clinical course. Although muscular dystrophies are also genetic disorders causing muscle weakness, they differ from congenital myopathies in age of onset, distribution of affected muscles, and the presence of characteristic dystrophic changes (eg, muscle fiber necrosis and regeneration) not present in biopsy specimens from congenital myopathies. The 3 most common types of congenital myopathy, in order, are Central core and multiminicore myopathies (core myopathies) Centronuclear myopathy Nemaline myopathy The types are distinguished primarily by their histologic features, symptoms, and prognosis. Diagnosis of congenital myopathiesis suggested by characteristic clinical findings and is confirmed by muscle biopsy and sometimes MRI of muscles. The genetic variants responsible for many of the different forms of congenital myopathy have been identified, and DNA testing is sometimes done depending on the results of clinical evaluation and other tests. Treatment of congenital myopathyis supportive and includes physical therapy, which may help preserve function. 