Depicted in Figure 84, 6-18fluoro-3-(1H-pyrrolo[2,3-c]pyridin-1-yl)isoquinolin-5-amine or [18F]MK-6240 is a second-generation tau PET tracer that targets neurofibrillary tangles (NFTs), which may be used for the detection and quantification of in vivo cerebral tau-pathology in AD (KD = 0.42 nM) [258]. This evidence concerns the gene MAPT and Alzheimer disease.