Intriguingly, after the discovery of C9orf72 repeat expansion as a genetic cause of FTLD as well as ALS with TDP-43 pathology, it was found that the minor allele in TMEM106b also protected against development of FTD, but not against ALS, in C9orf72 expansion carriers [51]. This evidence concerns the gene C9orf72 and frontotemporal dementia.