MAPT and Alzheimer disease: GRN and MAPT mutations are typically associated with FTLD, yet some individuals with mutated forms of these genes have exhibited phenotypes that are indistinguishable from AD (Rademakers et al. 2003b; Doran et al. 2007; Gijselinck et al. 2008; Fenoglio et al. 2009; Jin et al. 2012) as was observed in this study.