A better performance of the Aβ42/p-tau ratio over the other CSF biomarkers has been reported in previous studies on MCI prediction (Hansson et al., 2006; Mattsson et al., 2009; Buchhave et al., 2012; Parnetti et al., 2012; Roe et al., 2013) and differential diagnosis between AD and other dementias (Maddalena et al., 2003; Jong et al., 2006; Holtzman, 2011). The gene discussed is MAPT; the disease is dementia.