HTT and ring chromosome 6: Despite demonstrating penetration of everolimus into brain and modulation of its target, we were unable to demonstrate any protective effects in R6/2 HD mouse brain as determined by a detailed quantitative neuropathology study (Figure 3D-G) and using three independent methods to quantify mutant huntingtin levels (Figures 3G, 6, see also Additional file 1: Figure S1) all at 12 weeks of age.