Anti-NF155 and anti-contactin-1 IgG4 are the most frequently detected antibodies, representing 1 to 20% of chronic inflammatory demyelinating polyradiculoneuropathies, with anti-contactin-associated protein-1 and anti-NF140/186 syndromes occurring less frequently. This evidence concerns the gene CNTN1 and chronic inflammatory demyelinating polyradiculoneuropathy.