Anti-IgLON-5 disease presenting with axial dystonia and acetazolamide-responsive apnea

We present a 67-year-old male with anti-IgLON5 disease with cervical and upper trunk dystonic spasms. Intermittent hallucinations, occurring both with infections and without a precipitant, and hand tremors were also present. The MRI of the brain was nonspecific. The CSF results yielded positivity for IgLON5 antibodies, along with a CSF protein of 98. Treatment involved intravenous immunoglobulin, plasma exchange, and rituximab providing modest improvement in symptoms. The disease progressed to worsening apnea, without stridor or known aspiration, which resolved with acetazolamide. While acetazolamide has long been used for the treatment of sleep-breathing-related disorder, this is the first known case of its effective use in anti-IgLON5-related central hypoventilation. Additionally, this case demonstrates that axial dystonia with painful and disabling anterocollis can be a prominent feature of this disease.