FTLD-tau has been overrepresented in some naPPA cohorts (Hodges et al., 2004; Josephs et al., 2006a,b; Knibb et al., 2006; Snowden et al., 2007; Mesulam et al., 2008; Grossman et al., 2012), especially when associated with apraxia of speech (Josephs et al., 2006a; Snowden et al., 2007) and svPPA has been predominantly associated with TDP-43 pathology (Hodges et al., 2004; Josephs et al., 2006a; Snowden et al., 2007; Grossman et al., 2008); while bvFTD contains similar proportions of FTLD-tau and FTLD-TDP (Forman et al., 2006; Josephs et al., 2006b; Snowden et al., 2007). The gene discussed is MAPT; the disease is apraxia.