Ultrastructural myopathology in the molecular era.

Electron microscopy is an essential component of myopathology, both in diagnostics and research of neuromuscular diseases. Although recently reduced in the diagnostic armamentarium, it has greatly been expanded to mouse models in research. Mostly it is descriptive, but a few additional techniques in combination with transmission electron microscopy have been employed. Foremost among them is immunoelectron microscopy, which assists in guiding molecular analysis in hereditary conditions, but may be vital in diagnostics of certain acquired entities, e.g., undulating tubules in dermatomyositis and in those congenital myopathies where genes and mutations remain to be identified, as in cylindrical spirals myopathy and hexagonal crystalloid-body myopathy.