alpha-synuclein immunoreactivity is present in axonal swellings in neuroaxonal dystrophy and acute traumatic brain injury

The primary neuroaxonal dystrophies (NAD), which include infantile NAD and Hallervorden-Spatz syndrome (HSS), an characterized by dystrophic terminal axons and axonal swellings. Lewy bodies have been found in some cases. In P arkinson disease (PD) and dementia with Lewy bodies (DLB), Lewy bodies and neurites display prominent alpha-synuclein immunoreactivity. We examined 2 cases of HSS and 4 cases of infantile NAD with alpha-synuclein immunohistoc hemistry to test the hypothesis that these disorders with similar morpholog ical findings might share a biochemical phenotype. Furthermore, we compared them to 8 cases of secondary or physiologic NAD of various causes and 2 ca ses of recent traumatic head injury. alpha-Synuclein positive neuronal cyto plasmic inclusions, including Lewy bodies, and neurites were numerous in 1 HSS and 1 infantile NAD case. In addition, axonal spheroids were immunostai ned in all 6 cases of primary NAD, 5 cases of secondary NAD, and 2 cases of recent head injury. Axonal spheroids were faintly stained in the 3 physiol ogic NAD cases. alpha-Synuclein positive axonal swellings may suggest a mec hanism, such as axonal injury, leading to the neuronal cytoplasmic accumula tion of alpha-synuclein in NAD and other disorders.