NfL constitutes a core part of the axonal backbone and is an indicator of degeneration in large myelinated axons.35 Some of the weaker correlations with neuroimaging and brain regions could be due to the fact that NfL is tracking secondary axonal damage as the pathology in MSA primarily involves misfolded alpha-synuclein and oligodendroglia. Here, NEFL is linked to multiple system atrophy.