Walsh & Hoyt: Relationship Among the Different Congenital Myopathies

It is clear that individual patients may show structural alterations of muscle fibers that are ""characteristic"" of more than one type of congenital myopathy. The frequency with which such associations are encountered suggests some relationship among the different structural congenital myopathies. It is therefore likely that either the structural alterations are, in fact, insufficient to permit an exact classification of these disorders or that the production of structural abnormalities occurs as a continuum during muscle development and thus allows multiple patterns to emerge. Theoretical constructs view the congenital myopathies as errors in developmental stages of muscle embryogenesisfusion of myoblasts into multinuclear myotubes, nuclear migration, nerve-controlled differentiation of muscle fiber types, and growth. Although ""myopathic,"" they may have some neurogenic bases, given the determinant developmental roles that innervation and firing patterns have on muscle development, histochemistry, and trophism.