FUS and amyotrophic lateral sclerosis: Western blot analysis of brainstem tissue from a treated and an untreated ALS-FUSP525L patient compared to normal control tissue (Fig. 5c and Extended Data Fig. 7b) showed a considerable reduction of both total and P525L mutant FUS protein to nearly undetectable levels, showing that, as in the mouse, ION363 can effectively silence FUS in humans.