Nystagmus in Autoimmune Kelch-like Protein 11 (KLHL11) Encephalitis

Patients with germ cell tumors may develop paraneoplastic encephalitis, and immunoglobulin G autoantibodies to KLHL11 have been identified as a biomarker. This video demonstrates spontaneous downbeat nystagmus increased with eccentric fixation and in downgaze in a patient with autoimmune KLHL11 encephalitis, which may also include ataxia, diplopia, dysarthria, hearing loss, tinnitus, and vertigo. Click the Related Article link for demonstration of ataxia and illustration of dysarthria in the same patient, and for full clinical details from a case series of patients with testicular cancer-related KLHL11 encephalitis.