Some patients diagnosed (according to electrophysiological criteria) as “CIDP” were found to have antibodies (mainly IgG4, unable to activate complement) against some components of the paranodal junctions: Neurofascin-155 (NF155), Contactin-1 (CNTN1), and Contactin-associated protein-1 (Caspr1). This evidence concerns the gene CNTNAP1 and chronic inflammatory demyelinating polyradiculoneuropathy.