Angelman syndrome (AS) is a genetic disorder that causes developmental delay, intellectual disability, speech problems, seizures (epilepsy), and problems with movement and balance (ataxia). Individuals with AS have happy and excitable personalities, are frequently smiling and laughing, and usually flap their hands when they are excited. Most children with AS have difficulty sleeping. Other features of AS include an abnormal curve to the spine (scoliosis), a small head size (microcephaly), and light hair, skin and eyes. Certain facial features can be noticed in adults with AS, including deep-set eyes, widely spaced teeth, and a wide smile. People with AS tend to live a normal lifespan.
AS is caused by changes to the UBE3A gene, located on chromosome 15. People have two copies of the UBE3A gene, one they inherit from their mother and one from their father. The mother’s copy is normally turned on in the brain while the father’s copy is turned off. If a child has a change that causes the mother’s copy to be turned off, they will have no working copies and will then have AS. Most cases of AS are due to a child missing their mother’s copy of UBE3A (deletion). In some cases, the child has a change (mutation) in the mother’s copy of UBE3A; and in others, a child inherits both copies of UBE3A from their father and none from their mother (uniparental disomy).
Symptoms of AS are usually not present until 6 months of age. Trouble with crawling and talking are usually the first signs of developmental delay. Seizures appear around age 2. A diagnosis of AS is normally confirmed with genetic testing. There is not a cure for AS, but therapies are available to help a child reach their developmental potential. There are also medications to help control seizures. If your child has been diagnosed with AS, talk to their doctor about the most current treatment options. Support groups can connect you with other families affected by AS.