What Is Angelman Syndrome?

Medically Reviewed by Brunilda Nazario, MD on November 19, 2021

Angelman syndrome is a rare genetic disorder that shows up early in life. It mainly affects the nervous system and can lead to:

Despite these challenges, children with Angelman syndrome have a normal life expectancy. Their personalities can be happy and excitable, and it’s common for them to smile and laugh a lot. Even though they need long-term care, early treatment can improve some of their symptoms and boost their quality of life.

What Causes Angelman Syndrome?

Problems with a gene called UBE3A usually cause the condition.

Genes carry the genetic info that determines your traits. You get them in pairs from your parents, one copy of each gene from your mother and one from your father. Your cells usually use information from both copies, but in some cases, only one copy is active.

Normally in the brain, only the copy of the UBE3A gene from your mom stays active. Angelman syndrome usually happens when part of that copy is damaged or missing. Less often, it happens when a child gets two copies of the gene from their dad instead of one from each parent.

How Rare Is Angelman Syndrome?

Only about 1 in 12,000 to 20,000 people get the condition.

What Are the Symptoms of Angelman Syndrome?

The signs can vary from person to person. Some people have more severe symptoms than others. A baby with Angelman syndrome usually starts showing signs around 6 to 12 months. You might notice these symptoms:

Developmental delays. A baby up to 24 months old may:

  • Be unable to support their head or pull themselves up to stand
  • Take longer to start crawling
  • Have trouble feeding because of problems swallowing or sucking

Young children may take longer to walk, and their movements and balance may seem off.

Lack of speaking. Babies with the condition might not coo or babble. Young children might try to communicate without talking, either because they can’t speak yet or they only know a few words.

Trouble sleeping. Children with Angelman syndrome may need less shut-eye, and their sleep-wake cycles might be off.

Angelman syndrome facial features. A child’s face may mostly resemble their parents’. But some children have distinct features, like:

  • Prominent or noticeable chin
  • Deep-set eyes
  • Wide mouth with protruding tongue
  • Wide spaces between teeth
  • Unusually flat back of the head

Seizures. Not all children with Angelman syndrome get these, but those that do usually start having them around 1½ to 3 years old.

Some symptoms, like seizures and trouble sleeping, tend to get less severe or show up less often when a child with Angelman syndrome gets older. They may become less excitable, too.

But because of trouble with balance and moving, a teenager with the condition could struggle with weight or form a curve in the spine called scoliosis.

How Is Angelman Syndrome Diagnosed?

Doctors usually diagnose a child with the syndrome when they’re 1 to 4 years old. But because Angelman syndrome can look like other conditions -- including autism spectrum disorder, cerebral palsy, and Prader-Willi syndrome -- it sometimes gets misdiagnosed.

If you’re a parent and you’re worried that your baby might be showing signs of Angelman syndrome, talk to your doctor away. They can do genetic tests to find out.

The earlier in life your child is diagnosed with Angelman syndrome, the sooner they can get personalized support and or treatments to help them live their best life.

What Are the Treatments for Angelman Syndrome?

Children with Angelman syndrome usually benefit from:

  • Physical, speech, and occupational therapies
  • Behavioral therapy to manage sleep issues, hyperactivity, short attention span, or other problematic habits
  • Devices to help them communicate, like computer picture-based systems
  • Other types of support for communicating, like sign language

They may also need:

  • Medication for seizures called anticonvulsants
  • Drugs or surgery for a digestive problem called GERD (gastroesophageal reflux disease)
  • Braces or surgery for scoliosis

If you’re a parent, work closely with your child’s doctor, therapists, and other caregivers. You could also join a support group for Angelman syndrome. It may help to connect with other parents who understand what your family is going through.

Is There a Cure for Angelman Syndrome?

No. But some experts think there’s a good chance they’ll eventually find a cure.

So far, scientists have been able to reverse Angelman syndrome in lab experiments on mice. Still, treatments that show promise in animals don’t necessarily end up helping people.

Why Did It Used to Be Called ‘Happy Puppet Syndrome’?

That name was based on the observations of Harry Angelman, MD, the English doctor who discovered the condition.

Angelman saw three children who had similar symptoms, including intellectual delays, stiff and jerky movements, lack of speech, seizures, and happy demeanors. He later saw an oil painting called “A Boy With a Puppet” that reminded him of the children, and in 1965 he published a paper that described “puppet children.”

The condition became known as happy puppet syndrome. But in 1982, two University of Florida researchers studying the condition proposed changing its name to Angelman syndrome in honor of the doctor’s discovery.

Show Sources


National Organization for Rare Disorders: “Angelman Syndrome.”

Angelman Syndrome Foundation: “What Is Angelman Syndrome?” “History.”

MedlinePlus: “Angelman Syndrome.”

Mayo Clinic: “Angelman Syndrome.”

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