Angelman Syndrome Symptoms & Causes

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What causes Angelman syndrome?

Angelman syndrome is caused by a genetic mutation on chromosome 15. The name of this gene is UBE3A. Normally, people inherit one copy of the gene from each parent, and both copies become active in many areas in the body. Angelman syndrome occurs when only one copy of the gene is active in certain areas of the brain.

What are the risk factors?

There are no known risk factors for Angelman syndrome. In some cases, a family history may increase the chances of a baby having the disorder but the disease is rare, occurring in just 1 of every 10,000 people. If you already have a child with Angelman syndrome or are concerned about a family history, talking with your doctor or a genetic counselor may be helpful.

What are the symptoms?

Children with Angelman syndrome tend to have some, but not necessarily all, of the following behaviors and characteristics:

  • Hand flapping or walking with arms in the air
  • Jerky body movements
  • Stiffed-leg walk
  • Little or no speech
  • Attention deficits
  • Hyperactivity
  • Feeding problems, especially in infancy
  • Sleep problems and a need for less sleep than their peers
  • Delays in motor development
  • Frequent laughter that may occur at inappropriate times
  • Excitable personality
  • Tongue thrusting
  • Strabismus (crossing of the eyes)
  • Small head size with flatness in the back of the head
  • A lower jaw that juts out
  • Light pigmentation in the hair skin and eyes

Are there medical complications associated with the disorder?


Children with Angelman syndrome may have feeding difficulties, sleep problems and hyperactivity.

  • Feeding difficulties, such as problems sucking and swallowing, may occur during the first few months of life.
  • Sleep disorders, such as frequent waking, may need to be treated with medication or behavior therapy.
  • Hyperactivity tends to decrease as children get older, but many young children with Angelman syndrome may have short attention spans and move quickly from one activity to the next.

What is the prognosis of a child with Angelman syndrome?

People with Angelman syndrome have almost normal life spans. Adults are not usually able to live on their own but can learn basic household tasks and can live in group homes. Some individuals can have jobs in which they are supervised directly.

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