The high failure rate of trials of novel drugs for neurodegenerative diseases (NDDs), such as Alzheimer’s disease, can be attributed to various issues, including complex challenges in the selection of targets and clinical readouts, a lack of relevant biomarkers, and insufficient recognition of disease heterogeneity1. For example, in Parkinson’s disease, genetic variation among patients in clinical trials could translate into heterogeneous rates of progression for some clinical readouts, ...