Main clinical characteristics of AS
| Consistent (100%) | Frequent (more than 80%) | Associated (20–80%) |
|---|---|---|
| Adapted from Williams CA, et al. Angelman syndrome: consensus for diagnostic criteria. Am J Med Genet 1995;56:237–8. | ||
| *Although emphasised particularly in Harry Angelman’s first description, we have not found this to be a particularly useful sign. | ||
| †The characteristic behavioural phenotype has been shown to be perhaps the most useful diagnostic marker for AS. | ||
| Severe developmental delay | Delayed, disproportionate growth in head circumference, usually resulting in microcephaly by age 2 | Flat occiput |
| Speech impairment, no or minimal use of words; receptive and non-verbal communication skills higher than verbal ones | Seizures, onset usually <3 years of age | Occipital groove* |
| Movement or balance disorder, usually ataxia of gait and/or tremulous movement of limbs | Characteristic EEG with large amplitude slow spike waves and triphasic waves | Protruding tongue |
| Behavioural uniqueness†: any combination of frequent laughter/smiling; apparent happy demeanor; easily excitable personality, often with hand flapping movements; hypermotoric behaviour; short attention span | Tongue thrusting; suck/swallowing disorders | |
| Feeding problems during infancy | ||
| Prognathia | ||
| Wide mouth, widely spaced teeth | ||
| Frequent drooling | ||
| Excessive chewing/mouthing behaviours | ||
| Strabismus | ||
| Hypopigmented skin, light hair and eye colour (compared to family), seen only in deletion cases | ||
| Hyperactive lower limb deep tendon reflexes | ||
| Uplifted, flexed arm position especially during ambulation | ||
| Increased sensitivity to heat | ||
| Sleep disturbance | ||
| Attraction to/fascination with water | ||