An important advantage in our study is that we mainly retrieved prediagnostic samples of patients with sporadic ALS, and that we evaluated pNfH, which has been shown to be a more specific diagnostic biomarker in ALS than NfL.11 Supporting our findings is the fact that in patients with sporadic ALS diagnosed early, pNfH levels were already significantly elevated in CSF and blood.10, 19, 20. This evidence concerns the gene NEFL and amyotrophic lateral sclerosis.