Antibodies to the complex of voltage-gated K+ channels (VGKC) and associated neuronal membrane proteins (contactin-associated protein-2 (CASPR-2; axon); contactin-2 (ensheathing glial cells); leucine-rich glioma inactivated 1 protein (LGI-1; synapse)) are detected in the sera of patients with peripheral nerve hyperexcitability (acquired neuromyotonia), Morvan's disease and limbic encephalitis [1-3]. The gene discussed is CNTNAP2; the disease is Isaacs syndrome.