MAPT and frontotemporal dementia: Pathologically, neuronal inclusions containing abnormal forms of tau or TAR DNA-binding protein 43 (TDP-43) are the key forms associated with FTD, with the latter classified into four subtypes TDP-43 Type A – D (Lashley et al., 2015, Mackenzie et al., 2011, Mackenzie et al., 2010, Seelaar et al., 2010).