Angelman Syndrome

Written by Deanna Altomara
Medically Reviewed by Dan Brennan, MD on February 27, 2025
6 min read

Angelman syndrome is a rare condition that causes problems with growth and development. It’s caused by a genetic mutation (a change in your genes) that affects the nervous system.

It’s named after Harry Angelman, MD, the doctor who first described it.

Think of DNA as your body’s instruction manual. This manual is divided into chapters. The chapters are your genes. 

Your cells are constantly multiplying and making new copies of the DNA manual. This is especially important during pregnancy. If a page is damaged or goes missing during the multiplication process, it’ll be damaged or missing in future copies. This is called a gene change or mutation. 

Changes in the ubiquitin protein ligase E3A (UBE3A) gene are what trigger Angelman syndrome. It’s the gene that tells your body how to form your nervous system. Some people with Angelman syndrome have a “misprint” in the gene. Others are missing that chapter entirely. 

Every cell has two copies of each gene, one from each parent. This way, if one copy is damaged, the cell can use the other copy. But in some parts of the brain, cells only use the UBE3A gene from your birthing parent, whether that copy is damaged or not.

In rare cases, Angelman syndrome happens when you inherit two copies of the gene from your father.

How common is it?

About 1 in 12,000 to 20,000 people have Angelman syndrome.

Angelman syndrome risk factors

The mutation that causes Angelman syndrome is usually random and sudden. It’s not clear why this happens. Because it’s random, most people with Angelman syndrome don’t have a family history of the condition. But it can be passed down if a family member has it.

Everyone is different, and symptoms can change throughout life. But the most common signs of Angelman syndrome are:

  • Developmental delays (for example, not crawling or babbling by 6 months)
  • Learning disabilities
  • Speech challenges
  • Poor balance or challenges with walking or movement
  • Seizures
  • Trouble feeding

Angelman syndrome facial features

Many people with Angelman syndrome have similar facial features. These include:

  • Small head (microcephaly)
  • Short, wide skull (brachycephaly)
  • Large lower jaw (mandibular prognathia)
  • Wide mouth
  • Large tongue (macroglossia)
  • Gaps between teeth
  • Light-colored hair, skin, and eyes
  • Crossed eyes

Angelman syndrome symptoms in kids

Children with Angelman tend to have a happy, excitable personality. They laugh frequently and smile often. They may have sleep issues. Their attention span and sleep challenges usually improve over time.

Symptoms include:

  • Hand flapping
  • Hyperactivity
  • Short attention span
  • Sleep problems (including trouble sleeping or needing less sleep)
  • Curiosity about water

Signs of Angelman syndrome usually appear during the first few years of life. Most children are diagnosed by the time they’re 4 years old.

Angelman syndrome can look a lot like other conditions. Because of this, some children are misdiagnosed with:

  • Autism spectrum disorder
  • Cerebral palsy
  • Mowat-Wilson syndrome
  • Christianson syndrome
  • Pitt-Hopkins syndrome
  • Prader-Willi syndrome
  • Phelan-McDermid syndrome

Genetic testing is the only way to know for sure if someone has Angelman syndrome. A blood test will show if there are mutations in the UBE3A gene. 

Babies can be tested before they’re born. If the doctor notices growth issues during a prenatal ultrasound, they might suggest a type of genetic testing called noninvasive prenatal screening. It looks at tiny pieces of the unborn baby’s DNA that float in the mother’s blood. 

There’s no cure for Angelman syndrome, but people with the condition can lead happy, fulfilling lives. Medical treatment to manage some symptoms and complications might be necessary. 

For example, they may need:

  • Medication for seizures (anticonvulsants)
  • Physical therapy to improve balance
  • Braces to help with walking
  • Speech therapy
  • Communication aids, like sign language or technological devices
  • Behavioral therapy for attention problems
  • Medication for feeding problems and constipation

Angelman syndrome can cause many kinds of symptoms, so it’s important to have a team of doctors who specialize in different areas. Your child’s care team might include:

  • Pediatricians
  • Neurologists (brain and nervous system doctors)
  • Geneticists
  • Speech-language pathologists
  • Occupational and physical therapists
  • Behavioral therapists
  • Gastroenterologists (doctors who specialize in the digestive system)
  • Nutritionists

Every child with Angelman syndrome is unique with different strengths and challenges. What works for one may not work for another. But certain tips apply to most everyone. As a caregiver, it’s important to: 

  • Give your child any medications exactly as prescribed.
  • Get developmental assessments along with physical, occupational, and speech therapies.
  • Go to all follow-up medical visits and keep your child’s care team updated.

Caring for a child with a disability can be deeply rewarding. But it also can be tiring, both physically and emotionally. Try to make time for self-care and social support. Joining a support group where you can connect with others in similar situations may be helpful. Together, you can celebrate milestones and share advice when things get hard.

People with Angelman syndrome have a high risk of some health issues, including:

Trouble feeding. Babies might have a hard time sucking and swallowing, which could impact nutrition. Using a high-calorie formula can help them get enough nutrients and gain weight.

Hyperactivity. Many children with Angelman syndrome are high-energy and have trouble focusing. Usually, medication isn’t necessary. Their attention span tends to get better as they age.

Sleep problems. Children with Angelman syndrome may have a hard time falling and staying asleep, or they might need less sleep than other children their age. Medication and behavior therapy can help. Often, their sleep gets better as they age.

Scoliosis. This is a side-to-side curving of the spine.

Obesity. As they get older, many children with Angelman syndrome become overweight or obese.

Angelman syndrome is a lifelong genetic condition that causes trouble with movement and balance, speech challenges, and developmental delays. People who have it usually have happy, bubbly personalities. Talk to your child’s doctor if you notice any signs of developmental delays, like not crawling or babbling by 6 months. There’s no cure, but early treatment can help your child develop skills and live a long, happy life.

What is the life expectancy of someone who has Angelman syndrome? 

Many people with Angelman syndrome live a normal lifespan.

What is the behavior of children with Angelman syndrome? 

Many children with Angelman syndrome have happy and excitable personalities. They may flap their hands and have short attention spans.

What does a typical day look like for someone with Angelman syndrome? 

People with Angelman syndrome can work and go to school. But they may need certain accommodations and support. They’ll probably need help with day-to-day tasks throughout their lives.

What is the IQ of someone with Angelman syndrome? 

People with Angelman syndrome may have an IQ below 70.

Is having Angelman the same thing as having autism? 

Angelman syndrome and autism share a lot of symptoms, but they’re separate conditions.