It appears that in the majority of murine studies (12 of 18) neurogenesis is primarily impaired (excluding the conditional knockout studies which are not directly associated with FAD) (Table I). It is interesting to note that studies in which only one naturally occurring mutation of APP and or PS1 are used, a greater majority found impaired neurogenesis (12 of 14). Also, in both cases where only knockin technology was used, an impairment of neurogenesis was found (Wang et al., 2004; Zhang et al., 2006). Conversely, in all cases where mutations in APP were combined (triple or quadruple mutations) increased neurogenesis was found.
