Fig. 1

Intracellular distribution of HTT and p62 inclusions within HD. a Numerous HTT or p62 cytoplasmic inclusions can be found within some neurons, such as in this Betz cell of a 48-year-old woman with 45 CAG repeats. b Intranuclear HTT inclusions are occasionally found in nuclear clusters, particularly in individuals with > 50 CAG repeats. This example was from the calcarine cortex (BA17) of a 30-year-old man with 61 CAG repeats. c Dual staining for HTT (brown)/p62 (red) highlights p62 colocalization with HTT and wrapping of p62 around HTT. Inset (c′) shows a fortuitous dystrophic neurite with a long extension of p62 that emanates from and enwraps an extranuclear HTT inclusion. d The proportion of intranuclear HTT inclusions relative to total HTT inclusions varies in the neocortex and prevails in caudal neocortices, especially the calcarine cortex (BA17). Vertical lines indicate the median value for the respective neocortical region. Note that in the instance of BA17 where the absolute number of inclusions is least of all four cortical regions, only 54 individuals could have calculated ratios because 11 brains had no inclusions in BA17. Brown arrows indicate HTT labeling; red arrows indicate p62 labeling. Brown arrows with a red edge indicate p62 colocalizing with HTT. Scale bars: a–c: 50 µm, c′: 10 µm