Angelman syndrome, a neurogenetic disorder brought on by loss of the Ube3a gene, is often accompanied by nonepileptic myoclonus according to a study of 200 patients reported by the Massachusetts General Hospital and the Lurie Center for Autism.
- Myoclonus seizures were reported in 14% of patients with Angelman syndrome, with the first episode beginning before 8 years of age.
- The seizures were usually brief, unless the patient was experiencing myoclonic status, and EEGs showed interictal generalized spike and wave activity.
- 40% of patients older than 10 years had nonepileptic myoclonus.
- Nonepileptic myoclonus typically started during puberty or later.
- The nonepileptic myoclonus lasted from seconds to hours and always began in patients’ hands and, in some cases, spread to face and all extremities.
Pollack SF, Grocott OR, Parkin KA, et al. Myoclonus in Angelman syndrome [Published online ahead of print March 17, 2018]. Epilepsy Behav. https://doi.org/10.1016/j.yebeh.2018.02.006.