MAPT and Alzheimer disease: Next, we evaluated 18F-MK-6240 tau PET in 30 middle aged to older adult cognitively symptomatic former NFL players, a population at high risk for having underlying CTE [1]. 18F-MK-6240 tracer binding was compared to sample of cognitively unimpaired males from the Boston University (BU) and University of California San Francisco (UCSF) AD Research Centers (ADRCs) and the Wisconsin Registry for Alzheimer’s Prevention (WRAP) study.