This latter finding, in particular, seems to exclude the hypothesis that the accelerator effect of TBI on the manifestation of cognitive decline might be due only or mainly, to the detrimental effect of APOE4, which remains, though, the major well-known genetic risk factor for AD, AD onset, AD clinical and pathological severity, and DLB (41–43). The gene discussed is APOE; the disease is Lewy body dementia.