This is a very important article as it indicates what according to specialists and researchers the diagnostic criteria for Angelman syndrome (AS) are. As such it is an important guide for clinicians who have to make (or exclude) an AS diagnosis.
This report is an update from the 1995 consensus statement. Nowadays, a genetic confirmation of the AS diagnosis is common in most Western-countries. However, it should be noted that in 10-15% of the individuals, the clinical diagnosis cannot be confirmed by current genetic tests. For these patients, the clinical diagnosis of AS can only be made if the clinical features associated with AS are present.

Clinical features of AS:
A. Always present:
- Developmental delay, impaired functioning
- Trouble moving (like trembling, strange walking, instability, clumsiness ect.)
- Abnormal behaviour: this entails a combination of frequent laughter, being happy, easily excitable, often associated with hand flapping (seems like the child is pretending to be a bird) making waving gestures and possible hyperactivity in movements.
- Speech problems, this entails none or sparse use of words, non verbal communication (for example hand gestures) are more frequently used and are better developed than the verbal communication skills.
B. Frequently present (in more than 80%):

- Delayed growth of the head circumference
- Epileptic seizures often starting before the age of 3, the seizures often decrease in amount but never disappear.
- Abnormal EEG (measuring of brain activity)

C. Associated with Angelman syndrome (20-80% present in patients)
- Protruding tong
- Tongue thrusting; suck/swallowing disorders
- Feeding problems
- Frequent drooling
- Wide mouth, teeth standing far apart
- Excessive chewing/mouthing behaviors
- Little colour in skin, light hair and eye colour compared to family members
- Constipation
- Scoliosis (curving of the spine)
- Obesity (in older children)
- Abnormal food behaviour (example excessive eating)
- Attraction/fascination with water
- Diminished need for sleep
- Increased sensitivity to heat
Others are mentioned in the C category that are very difficult to explain and are probably only recognized by physicians.

To make a definitive diagnosis a DNA test can be done to find a characteristic pattern.



Title: Angelman syndrome 2005: Updated Consensus for Diagnostic Criteria
Authors: Williams CA, Beaudet AL, Clayton-Smith J, Knoll JH, Kyllerman M, Laan LA, Magenis RE, Moncla A, Schinzel AA, Summers JA, Wagstaff J.
Journal: American Journal of pediatrics
(Contributed by Caroline Bruinsma & Ype Elgersma, Erasmus MC, Rotterdam, The Netherlands).