Recent studies done using data from the Alzheimer’s Disease Neuroimaging Initiative have shown that an increase in CSF-phosphorylated-tau, which is an AD-specific CSF marker, may precede tau-PET positivity (Meyer et al., 2020), meaning that an increase in CSF-total-tau could be indicative of early stage disease and thus the risk of progression is lower when only this marker is abnormal. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.