TARDBP and Alzheimer disease: About 25-45% cases of AD also show (secondary) TDP-43 pathological changes within the amygdala, hippocampus, and sometimes also in neocortical regions[21-24], the proportion of ‘positive’ cases seemingly being dependent upon how extensively the brain is sampled[21] Cases are frequently encountered where TDP-43 pathological changes are confined to the amygdala, and consequently such ‘incidental’ cases may be considered negative if this region is not examined[21].