Paroxysms of laughter have no relation to the EEG, ruling out this feature as a gelastic phenomenon.EEG anomalies may be used as a quantitative biomarkers to "chart progression of AS and as clinical outcome measures". Slow delta activity (~3 Hz) is greatly increased in AS relative to typically developing children, yet more pronounced in children with partial 15q deletions as opposed to those with etiologies principally affecting UBE3A. Theta activity (~5 Hz) is much greater in children with partial 15q deletions. Thus, delta activity appears to be chiefly reflective of UBE3A dysfunction with some modulation from other 15q genes, whereas theta activity may be an electrophysiological readout of genes beyond UBE3A such as GABRA5, GABRB3, and GABRG3. Future clinical trials in AS might exploit the foregoing by using EEG as a readout of drug target engagement.It appears that the neurons of people with Angelman syndrome are formed correctly, but they cannot function properly. Diagnosis
The diagnosis of Angelman syndrome is based on:
A history of delayed motor milestones and then later a delay in general development, especially of speech
Unusual movements including fine tremors, jerky limb movements, hand flapping and a wide-based, stiff-legged gait. Characteristic facial appearance (but not in all cases). A history of epilepsy and an abnormal EEG tracing.
Early and continued participation in physical, occupational (related to the development of fine-motor control skills), and communication (speech) therapies are believed to significantly improve the prognosis (in the areas of cognition and communication) of individuals affected by AS. Further, the specific genetic mechanism underlying the condition is thought to correlate to the general prognosis of the affected person. On one end of the spectrum, a mutation to the UBE3A gene is thought to correlate to the least affected, whereas larger deletions on chromosome 15 are thought to correspond to the most affected.The clinical features of Angelman syndrome alter with age. As adulthood approaches, hyperactivity and poor sleep patterns improve. The seizures decrease in frequency and often cease altogether and the EEG abnormalities are less obvious. Medication is typically advisable to those with seizure disorders. Often overlooked is the contribution of the poor sleep patterns to the frequency and/or severity of the seizures. Medication may be worthwhile to help deal with this issue and improve the prognosis with respect to seizures and sleep. Also noteworthy are the reports that the frequency and severity of seizures temporarily escalate in pubescent Angelman syndrome girls, but do not seem to affect long-term health.The facial features remain recognizable with age, but many adults with AS look remarkably youthful for their age.Puberty and menstruation begin at around the average age.