Importantly, strong evidence suggests that MRI, FDG-PET, and CSF tau biomarkers are already abnormal in the MCI phase of AD (Ewers et al., 2007; Sluimer et al., 2008; Shaw et al., 2009), and while both CSF tau and MRI are predictive of conversion from MCI to AD, the predictive power of structural MRI is greater. This evidence concerns the gene MAPT and Alzheimer disease.