Chorea-acanthocytosis masquerading as a progressive seizure disorder with apparent early immunotherapy responsiveness

Chorea-acanthocytosis (ChAc) is a rare genetic disorder characterised by a hyperkinetic movement disorder, dystonia, cognitive and neuropsychiatric deficits and seizures. We report the case of a 30-year-old patient who presented with a decade of episodic neurological dysfunction and seizures. The condition was initially suspected to be an immunotherapy-responsive seronegative autoimmune encephalitis but progressed to oromandibular dystonia, raising suspicion of a neurodegenerative condition. Neuroimaging showed bilateral caudate atrophy and acanthocytes were seen on blood film microscopy in association with raised creatine kinase. Genetic testing revealed our patient to be compound heterozygous for two pathogenic variants in the VPS13A gene and confirmed the diagnosis of ChAc. This case highlights the importance of considering ChAc in the differential diagnosis of a progressive treatment-refractory seizure disorder in the context of oromandibular dystonia.