A recent wealth of genetic and neuropathological data has enabled certain clinical PPA phenotypes to be correlated with particular pathological substrates: for example, sv-PPA is predominantly associated with TAR DNA-binding protein 43 (TDP-43) type C pathology and lv-PPA with Alzheimer's disease (AD) pathology (Grossman, 2010; Rohrer et al., 2011; Whitwell and Josephs, 2011). This evidence concerns the gene TARDBP and primary progressive aphasia.