This review will systematically assess the development of second-generation tau PET tracers (i.e., 18F-RO-948, 18F-MK-6240, 18F-PI-2620, 18F-JNJ-311, 18F-GTP1) as biomarkers of AD, by evaluating the achievement of the validation aims defined by the strategic biomarker roadmap (2017; 2020). This evidence concerns the gene MAPT and Alzheimer disease.