Terminal axon pathology in infantile neuroaxonal dystrophy.

In order to clarify the pathogenesis of infantile neuroaxonal dystrophy, ultrastructural studies of the terminal and nonterminal axons of motor and autonomic nerves in muscle and skin, of which structures are much simpler than those of the central nervous system, were performed in 5 patients affected by infantile neuroaxonal dystrophy. The primary lesion was located in the axon terminal; the majority of terminal axons were dystrophic with tubulo-membranous profiles, while there were only a few dystrophic axons in the nonterminal axons. According to these findings, it is logical to consider that interruption of axonal transport at the site of the "turnaround" process is a cause of dystrophic change of the terminal axon in infantile neuroaxonal dystrophy.