56.: Phenotypic variation in Miller Fisher syndrome

This study aims to describe the diverse clinical presentations associated with anti-GQ1b antibody positivity. We report four patients with Miller Fisher Syndrome (MFS) admitted over a period of 3 months to a single tertiary hospital in Sydney, NSW, Australia. Only one patient presented with the classical clinical triad of ataxia, areflexia and ophthalmoplegia. The three other patients presented with a range of signs including blepharoptosis, pseudo-internuclear opthalmoplegia and pseudo-proptosis. Two patients had positive repetitive nerve stimulation and were mistaken for ocular myasthenia gravis. All patients had strongly positive immunoglobulin G anti-GQ1b antibodies detected. While the diversity of clinical presentations delayed formal diagnosis, treatment with intravenous immunoglobulin therapy prompted a complete recovery in all patients. Our patients highlight the spectrum of clinical features associated with GQ1b antibodies. While the classic triad of acute ophthalmoplegia, ataxia, and areflexia is a highly recognisable clinical entity, anti-GQ1b antibody-related disease should also be suspected in patients with limited or atypical forms of Miller Fisher syndrome.