Variants in UBQLN2 were found to be causative for X-linked forms of ALS and ALS/FTD [202,203,213,214], and results in the presence of UBQLN2 in neuronal cytoplasmic aggregates positive for ubiquitin, p62 and TDP-43 [202,215]. This evidence concerns the gene SQSTM1 and frontotemporal dementia.