In f-FTLD, serum NfL is associated with disease severity, brain volume, and brain atrophy.18 In symptomatic sporadic FTLD, baseline serum NfL correlated with executive function and brain atrophy, but not with longitudinal change in neuropsychological scores,17 which is similar to what we observed in participants with full phenotype. This evidence concerns the gene NEFL and Brain atrophy.