Analysis of DNA from brain tissue on stereo-EEG electrodes reveals mosaic epilepsy-related variants.

Somatic mosaic variants contribute to focal epilepsy, but genetic analysis has been limited to patients with drug-resistant epilepsy (DRE) who undergo surgical resection, as the variants are mainly brain-limited. Stereoelectroencephalography (sEEG) has become part of the evaluation for many patients with focal DRE, and sEEG electrodes provide a potential source of small amounts of brain-derived DNA. We aimed to identify, validate, and assess the distribution of potentially clinically relevant mosaic variants in DNA extracted from trace brain tissue on individual sEEG electrodes.

Intralesional epileptiform activity in a fourth ventricular hamartoma associated with epileptic hemifacial spasm in a toddler: illustrative case.

Background: Focal epilepsy caused by a posterior fossa lesion is a rare phenomenon. In these cases, seizure onset typically occurs during the first few months of life, with episodes of epileptic hemifacial spasms and abnormal eye movements. Patients often present with drug-resistant epilepsy and often require resection for the best chance of seizure freedom.

The spectrum of movement disorders in young children with ARX-related epilepsy-dyskinesia syndrome.

Children with developmental and epileptic encephalopathies often present with co-occurring dyskinesias. Pathogenic variants in ARX cause a pleomorphic syndrome that includes infantile epilepsy with a variety of movement disorders ranging from focal hand dystonia to generalized dystonia with frequent status dystonicus. In this report, we present three patients with severe movement disorders as part of ARX-associated epilepsy-dyskinesia syndrome, including a patient with a novel pathogenic missense variant (p.