Adult onset type II fiber centronuclear neuromyopathy with segmented demyelination.

We report a 54-year-old male with progressive, adult onset distal muscle weakness and intermittent paresthesia associated with preferential type II fiber centronuclear (myotubular) change and segmental demyelination in sural nerve. Morphometric analysis, single fiber teasing and graphic analysis of internode lengths confirms the segmental demyelination with no evidence of ongoing repetitive Schwann cell remyelination. Cases of adult onset centronuclear myopathy are reviewed. This cas provides evidence for a neurogenic component in the pathogenesis of the centronuclear neuromyopathies.