SLC1A3 and Alzheimer disease: This increased sensitivity when measuring sorted cells confirms our previous observations that a difference between AD and control subjects only appeared after cell sorting.24 Two factors likely contribute to this: 1) amalgamation of multiple cell types in data derived from PET imaging ‘dilutes’ the genotype effects measured in GLAST+ cells that were not seen in other cell types, and 2) partial volume effects, which reduce PET sensitivity, particularly in areas in close proximity to CSF (e.g. the hippocampus), but do not affect MACS-RTT measurements.