C9orf72 and behavioral variant of frontotemporal dementia: Since we were primarily interested in the sporadic, non-genetic bvFTD, we examined our samples for mutations in the genes C9orf72, GRN and MAPT. A total of 41 of the 48 bvFTD and 20 of the 48 AD cases were tested negative for the most prominent gene C9orf72. Further, no mutations in the genes MAPT and GRN were identified in the tested AD (n = 11) and bvFTD (n = 11) cases.