Treating GNAO1 mutation-related severe movement disorders with oxcarbazepine: a case report

GNAO1 variants have been found to be associated with epileptic encephalopathies, developmental delays (DDs), and movement disorders (MDs). Therapies for patients with GNAO1 variants vary. However, treatments for GNAO1-related diseases are still in their infancy. Previous reports suggest that few pharmacological treatments are effective for patients with GNAO1 variant-related MDs. Deep brain stimulation (DBS) treatment appears to be effective, however surgical procedures and equipment failures pose risks to the patients. Effectiveness for oxcarbazepine (OXC) in GNAO1 variant-related MDs is first reported in our study, and it expand the effective drugs for MD treatment.

We report the case of a 5-year-old male patient with a MD, who suffered from hypotonia and refractory choreoathetosis. The patient was found to have a DD and an intellectual disability. A de-novo variant of the GNAO1 gene (NM_138736: exom6: c.709G>A [p. Glu237Lys]) was identified by whole exome sequencing (WES) when he was 8 months old. The patient visited our hospital at the age of 4 years and 3 months because of fever and recurrent convulsions. Electroencephalogram (EEG) results show abnormal spikes, and magnetic resonance imaging (MRI) showed the enlargement of the lateral ventricles. The administration of tiapride hydrochloride, phenobarbital, midazolam, and hormones had no effect. OXC treatment was then initiated. No MD behaviors, such as rigidity and twisting of the limbs and trunk, or chorea, were observed after 10 days OXC treatment. Eventually, incremental doses of OXC were effective, and our patient achieved good control of his MD.

We are the first to demonstrate the role of OXC in alleviating MDs associated with GNAO1 mutations. This report provides a novel possibility for the clinical treatment of this rare disease. To manage MDs associated with GNAO1 mutations, we recommend that OXC treatment be attempted before invasive surgical therapy.