Reduction of neuronal specific protein and some neurotransmitters in the infantile neuroaxonal dystrophy (INAD).

INAD with classical clinicopathological features was seen in three children of one family. They presented with a history of regression after the age of 1.5 years and died in mental institutions at the ages of 6, 7 and 9. Two of them had postmortem neuropathological studies, one had brain biopsy and one biochemical study. The following observations have been made; I. Histological--(1) some axonal loss with almost total absence of neurofilaments in dystrophic neurites and (2) marked degenerative changes and loss of synaptic vesicles; II. Biochemical--(1) the decrease of the neurofilament polypeptides by up to 75% and (2) a reduction of some neurotransmitter enzymes. The presence of intermitochondrial septate junctions. The neurofilament protein is specific to neurons and makes up a large percentage of their protein content. Neurofilaments have been implicated in several cellular functions such as intracellular transport and in the maintenance of cell structure. The decrease of neurofilament protein in our case is compatible with our morphological findings where we found decreased numbers of axons and an almost total absence of neurofilaments in the affected neurites.