[The first case of Miller Fisher syndrome associated with anti-GM3 IgG antibodies: Classic triad and an atypical immune response].

Abstract

Miller-Fisher syndrome (MFS) is a rare variant of Guillain-Barré Syndrome (GBS), an acute immune-mediated peripheral neuropathy most preceded by infections, particularly Campylobacter jejuni, through a mechanism of molecular mimicry that underlies its predominantly autoimmune pathogenesis. Anti-ganglioside antibodies play a significant role in the pathogenesis of MFS, with a particularly high prevalence of anti-GQ1b antibodies among affected individuals. However, the presence of alternative anti-ganglioside antibodies does not exclude the diagnosis. We report the case of a 72-year-old male who presented with acute-onset diplopia and progressive visual impairment in both eyes, accompanied by gait imbalance. He had a history of gastroenteritis approximately two weeks prior to symptom onset. Neurological examination revealed near-complete ophthalmoplegia with severe diplopia in all directions of gaze, generalized hyporeflexia in the limbs, and impaired coordination. Cerebrospinal fluid analysis was unremarkable. Anti-ganglioside antibody testing was performed using enzyme-linked immunosorbent assay for antibodies against GM1, GM2, GM3, GD1a, GD1b, GT1b, and GQ1b. The results showed isolated strong positivity (+++) for anti-GM3 IgG antibodies. Based on clinical presentation and serological findings, a diagnosis of Miller-Fisher syndrome was established. The presence of anti-ganglioside antibodies may serve as supportive evidence for MFS, but the diagnosis remains primarily clinical.