Voltage-gated potassium channels (VGKC) are essential for the cellular action potential. Antibodies against the VGKC-complex are associated with a wide spectrum of diseases involving both the peripheral and central nervous system, including neuromyotonia, Morvan disease, limbic encephalitis, faciobrachial dystonic seizures and cerebellar ataxia.1 Leucine-rich, glioma-inactivated 1 antigen (LGI1) and contactin-associated protein-2 (Caspr2) have been found to be part of the VGKC-complex and targets for auto-antibodies.2 ,3 However, for the majority of the VGKC-complex antibodies, the specific antibody targets remain unknown. Moreover, apart from a recent study,4 little information exists on the relevance of VGKC-complex antibody level and neurological diseases, or the subgroups of VGKC antibodies and the presence of other encephalitic or paraneoplastic antibodies. We decided therefore to characterise our patients according to these parameters. The study was approved by the regional committee for medical and health research ethics in Western-Norway.

We identified 36 patients tested positive for VGKC-complex antibodies (tested by radioimmunoprecipitation in Oxford, >100 pM) at Haukeland University Hospital, Bergen, Norway, between 2001 and 2012. The sera were sent by neurologists who decided the indications for the test. The highest VGKC-complex antibody level was chosen for each patient (table 1). Two patients were of foreign origin and excluded …