Our mass spectrometry analysis identified clusterin as an abundant exosome-associated protein (online supplementary figure 3E), which is a known risk gene26 27 for Alzheimer’s dementia and was shown to interact with TDP-43 and tau in functional studies.28 We, therefore, hypothesised that the quantification of clusterin in neuronal exosomes may aid the stratification of patients. Here, MAPT is linked to Alzheimer disease.