A breakthrough in CIDP antibody autoimmunity has been the remarkable observation that a subset of patients who do not respond to IVIg or plasmapheresis have IgG4 antibodies to nodal/paranodal antigens directed against neurofascin-155 (Nfasc155), neurofascin-140/186 (Nfasc140/186), contactin-1 (CNTN1), and contactin-associated protein 1 (Caspr1) [1, 7, 15–19]. This evidence concerns the gene CNTNAP1 and chronic inflammatory demyelinating polyradiculoneuropathy.