We merged patient from monocentric retrospective and multicentre prospective studies and assigned them to 3 major cohorts, namely “active CIDP/AIDP” (n = 61), “other neurological diseases” (OND; n = 87), and “non-immune-mediated axonal neuropathies” (n = 26).27,28 Then, we used the validated cutoff for SM (0.9819 pmol/μL) to compare these groups, displaying the strength of our assay to unambiguously identify demyelination typical of active CIDP and AIDP (P < .0001; Figure 5A). This evidence concerns the gene PMP22 and Guillain-Barre syndrome, familial.