C9 and frontotemporal dementia: Of 345 C9+ ALS/FTD probands (where expansion size was investigated by Southern blotting), 13 showed atypical expansions of 50–200 repeats (3.8%), including 2 cases where the 50–200 repeat allele occurred in conjunction with a large expansion (Buchman et al., 2013, Waite et al., 2014).