Objective:

To characterize genetic, clinical, developmental, and treatment-response features of epilepsy-dyskinesia syndromes in children.

Approach:

• Study design and participants: Multinational cross-sectional study of 609 pediatric patients with childhood-onset movement disorders and pathogenic variants in 105 predefined genes.
• Data collection and analysis: More than 30 centers in 25 countries used a standardized survey. Researchers analyzed clinical features and treatment responses and used unsupervised clustering with protein-interaction and functional data.

Key Findings:

• Pathogenic variants were identified in 74 genes; 12 genes accounted for two-thirds of cases.
• Dystonia, stereotypies, and ataxia were the most common movement disorders, and mixed movement-disorder presentations were frequent.
• Epilepsy was reported in approximately two-thirds of patients.
• Developmental outcomes and medication responses varied by genetic etiology and pathway.
• The study confirmed carbamazepine responsiveness in PRRT2-related disease and reported worsening motor symptoms with levodopa/carbidopa in patients with GNAO1 or MECP2 variants.

Interpretation:

The study identified substantial clinical and genetic diversity across epilepsy-dyskinesia syndromes, including patients whose presentation may be more movement-disorder-focused than seizure-focused.

Limitations:

• The study was cross-sectional and relied on standardized survey data.
• The supplied context does not report additional study limitations.

Sources:

• Quiroz V, et al. Brain. 2026;149(2):563–578. doi:10.1093/brain/awaf297. PMID: 40811633.