The least yet still significantly affected white matter tracts in bvFTD patients were the corticospinal tracts (CST), previously shown to degenerate, to some extent, in frontotemporal lobar degeneration (associated with FTD clinical syndrome) with TDP-43 immunoreactive inclusions (Josephs et al. 2013). The gene discussed is TARDBP; the disease is behavioral variant of frontotemporal dementia.