Torsina immunoreactivity in normal and DYT1 brain - Light microscopic studies in DYT1 human and electron microscopic studies in non-human primate brain

A mutation of the DYT1 gene, which codes for torsinA, has been identified as the cause of one form of autosomal-dominantly inherited dystonia. We used a recently-developed polyclonal antibody to examine torsinA immunohistochemistry in the brain of a patient with generalised DYT1 dystonia and in several cases of non-DYT1 dystonia. We found no evidence of alterations of torsinA immunoreactivity at the light microscopic level, specifically no cytoplasmic aggregations nor co-localisation of torsinA immunoreactivity with a marker for endoplasmic reticulum. These findings contrast with results of recent cell culture studies of torsinA. Electron microscopic examination of patus monkey brain immunolabelled for torsinA confirmed the presence of torsinA in the neuronal nucleus, in nerve terminals, and also in axons. TorsinA may play a universal role throughout the brain, with the DYT1 mutation interfering with the function of a specific subset of neurons, which is not reflected in alterations in immunohistochemistry at the light microscope level.