Abstract
Angelman syndrome (AS) is a neurodevelopmental disorder associated with a unique type
of epilepsy. AS is caused by loss of function of the ubiquitin protein ligase E3A
(UBE3A) gene. Most cases of AS (70%) are caused by an approximate 5 Mb deletion in chromosome
15q11-q13 of the maternally derived allele; other causes include paternal uniparental
disomy of chromosome 15 (5%), imprinting defects (5%), and UBE3A mutations (10%), with the genetic cause yet to be determined in the remaining 10%
of cases. Many seizure types are present in AS, with myoclonic, absence, and tonic–clonic
seizures being common. Characteristic findings of electroencephalography in AS include
persistent rhythmic theta activity, anterior dominant rhythmic high-amplitude delta
(2–3 Hz) activity or spikes and slow waves, and posterior dominant spikes and sharp
waves mixed with 3 to 4 Hz high-amplitude slow waves. UBE3A has been shown to regulate both the glutamatergic and gamma-aminobutyric acidergic
systems; further dissection of the molecular mechanisms of UBE3A action in mouse models and individuals with AS would facilitate a greater understanding
of the pathophysiology of epilepsy.
Keywords
Angelman syndrome -
UBE3A
- electroencephalography - tonic inhibition
