NEFL and Alzheimer disease: Neurofilament light (NfL) is a scaffolding cytoskeleton protein (Strydom et al., 2013) and blood concentrations of NfL correlate well with axonal damage in neurological disorders, including in AD (Mattsson et al., 2017; Weston et al., 2017) and DS (Strydom et al., 2018).