It adds complexity to current AD diagnosis methods involving measurement of pathology, and urges researchers to focus on more functional clinical endpoints for AD, such as scores on screening tests of cognitive performance like the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) or biomarkers of synaptic loss, such as positron emission tomography (PET) scans for the presynaptic marker SV2A, which has been reported to reflect synapse number (Arevalo-Rodriguez et al., 2021; Davis et al., 2021; Finnema et al., 2016). This evidence concerns the gene SV2A and Alzheimer disease.