Neuropathologic and morphometric studies in hereditary motor and sensory neuropathy type II with neurofilament accumulation.

Histological, electron microscopic and morphometric data on sural nerve, muscle, and skin biopsies of three patients affected by autosomal dominant hereditary motor and sensory neuropathy type II with neurofilament accumulation, whose neurological, cardiological and electrophysiological data have been provided in a previous paper disclosed focally enlarged myelinated axons, due to aggregation of neurofilaments in sural nerves of all 3 biopsied patients, as well as densely packed clusters of filaments in occasional non-myelinated axons without axonal enlargement, in several fibroblasts and endothelial cells in muscle and particularly in skin. This accumulation of filaments was less pronounced in our patients' tissues than in autosomal-recessive GAN. No ultrastructural differences concerning the accumulated filaments appear to exist between the affected cells of our patients and GAN. Taken together, these findings best fit a hereditary motor and sensory neuropathy type II with focal accumulation of intra-axonal neurofilaments.