Although the plasma concentration of TDP-43 has been observed to be elevated in patients with FTLD, since TDP-43 has a low concentration in cerebrospinal fluid (CSF) and may mainly originate from blood, its correlation with neurodegeneration in AD is still controversial (Foulds et al., 2008; Foulds et al., 2009; Williams et al., 2017). Here, TARDBP is linked to Alzheimer disease.