Cytoskeletal changes and ubiquitin expression in dystrophic axons of Seitelberger's disease

Central nervous system specimens of 4 cases of Infantile Neuroaxonal Dystrophy (Seitelberger's disease) were processed for Bodian's silver stain and for immunostaining with antibodies against neurofilaments (NF), tubulin and ubiquitin (UBQ). Reactivity to NF and UBQ was restricted to spheroids of small size; swellings larger than 30 mu were negative, in spite of their positivity to Bodian's silver stain. Reactivity to tubulin was evident only in normal fibers, whereas no positive material was observed in dystrophic axons. These findings suggest that loss of microtubules (MT) and denaturation of NF might play a crucial role in the mechanisms responsible for the formation of axonal spheroids; in addition the focal activation of the UBQ system suggests an attempt of the neuron to remove abnormal material even at sites remote from the perikaryon.