Anti-MAG neuropathy: Role of IgM antibodies, the paranodal junction and juxtaparanodal potassium channels

•Anti-MAG neuropathy is associated with proximal nerve enlargement.•Changes in juxtaparanodal fast potassium channel function may underlie nerve dysfunction.•Potassium channels blockers may hence improve nerve function. To improve understanding of disease pathophysiology in anti-myelin-associated glycoprotein (anti-MAG) neuropathy to guide further treatment approaches. Anti-MAG neuropathy patients underwent clinical assessments, nerve conduction and excitability studies, and ultrasound assessment. Patients demonstrated a distinctive axonal excitability profile characterised by a reduction in superexcitability [MAG: −14.2 ± 1.6% vs healthy controls (HC): −21.8 ± 1.2%; p