TARDBP and amyotrophic lateral sclerosis: In addition to RNA foci and DPR pathology, C9orf72 patients also develop TDP‐43 pathology that correlates well with neurodegeneration like in other forms of FTLD/ALS (Mackenzie et al, 2013), but it is still unclear how the C9orf72 repeat expansion triggers TDP‐43 pathology.