Bilateral Internuclear Ophthalmoplegia Associated with Anti-GQ1b Antibody

Anti-GQ1b antibody is often associated with acute ophthalmoplegia, and various diseases which have this antibody and ophthalmoplegia, including Miller Fisher syndrome, Bickerstaff's brainstem encephalitis, Guillain-Barre syndrome, acute ophthalmoplegia (without ataxia) are referred to as anti-GQ1b antibody syndrome. Internuclear ophthalmoplegia (INO) is a disorder of conjugate lateral gaze in which the affected eye shows impairment of adduction that is caused by a lesion in the medial longitudinal fasciculus (MLF). Common etiologies of INO are stroke and demyelinating disorders invading the MLF. Previously, Miller Fisher syndrome has manifested as an INO; however, it is usually called a pseudo-INO since it might not be related to a true MLF lesion. We report a case of anti-GQ1b antibody syndrome with atypical clinical manifestations; true MLF syndrome.