Considering a group of patients attributable to the probable early onset of AD (EOAD), CSF biomarkers allow us to identify three clusters: the first with low levels of Aβ42 and normal levels of t-Tau and p-Tau; the second with low levels of Aβ42 and high levels of t-Tau and p-Tau; and finally, the third with very high levels of t-Tau and p-Tau and low-normal levels of Aβ42. Here, MAPT is linked to Alzheimer disease.