Actin, alpha skeletal muscle

Congenital myopathy 2A, typical, autosomal dominant

A muscular disorder characterized by generalized muscle weakness, delayed motor milestones, hypotonia, and muscle fiber abnormalities on histologic examination. Histologic findings include abnormal thread- or rod-like structures (nemaline rods), intranuclear rods, clumped filaments, cores, or fiber-type disproportion. The spectrum of clinical phenotypes ranges from severe neonatal presentations to onset of a milder disorder in childhood.

Congenital myopathy 2B, severe infantile, autosomal recessive

An autosomal recessive skeletal muscle disorder characterized by severe hypotonia with lack of spontaneous movements and respiratory insufficiency, usually leading to death in infancy or early childhood. Longer survival has been reported.

Congenital myopathy 2C, severe infantile, autosomal dominant

An autosomal dominant skeletal muscle disorder characterized by severe congenital weakness usually resulting in death from respiratory failure in the first year or so of life. Patients present at birth with hypotonia, lack of antigravity movements, poor head control, and difficulties feeding or breathing, often requiring tube-feeding and mechanical ventilation. Decreased fetal movements may be observed in some cases.

Myopathy, scapulohumeroperoneal

An autosomal dominant muscular disorder characterized by progressive muscle weakness with initial scapulo-humeral-peroneal and distal distribution. Over time, muscle weakness progresses to proximal muscle groups. Clinical characteristics include scapular winging, mild lower facial weakness, foot drop due to foot eversion and dorsiflexion weakness, and selective muscle atrophy. Age at onset and disease progression are variable.