The combination of the lower pathological tau load in CTE brains when compared to AD and the apparent differential affinity of this imaging agent for disease-specific molecular conformations of tau filaments suggest that [18F]-AV-1451 may not be an optimal agent to use for assessment of CTE, particularly in older individuals where the presence of concomitant AD pathology is a frequent finding. This evidence concerns the gene MAPT and Alzheimer disease.