Nemaline myopathy 1

Nemaline myopathy-1 is a disorder characterized by muscle weakness, usually beginning in early childhood. The severity and pattern of muscle weakness varies, but most affected individuals show mildly delayed motor development, hypotonia, generalized muscle weakness, and weakness of the proximal limb muscles and neck muscles, resulting in difficulty running and easy fatigability. Most patients have respiratory insufficiency due to muscle weakness. Other common features include myopathic facies, high-arched palate, and scoliosis. Histologic findings on skeletal muscle biopsy are variable, even in patients with the same mutation. Muscle fibers can contain nemaline rod inclusions, or so-called subsarcolemmal 'cap' structures, as well as show overall fiber-type disproportion. It has been suggested that unknown modifying factors confer a tendency to one or another pattern of inclusions on skeletal muscle biopsy in those with TPM3 mutations (summary by Waddell et al., 2010 and Malfatti et al., 2013). For a discussion of genetic heterogeneity of nemaline myopathy, see 161800.

OMIM