Angelman Syndrome

Angelman syndrome is a rare genetic condition that affects your child’s development, speech, balance and movement. It may also cause seizures.

At first, you may notice that your child is unusually happy compared to others their age. They may smile frequently and laugh a lot. When they’re excited, they may make hand-flapping motions. Other signs and symptoms tend to appear as your child gets older, like developmental delays and seizures.

This condition isn’t life-threatening and shouldn’t affect your child’s life expectancy. There’s no cure. But treatments can help with symptoms. Your child’s healthcare provider will tailor a treatment plan to fit your child’s needs.

Symptoms of Angelman syndrome

Symptoms and features vary from person to person and with age. Common signs and symptoms of Angelman syndrome include:

• Developmental delays, like not saying their first word before their first year
• Intellectual disability
• Speech challenges, ranging from not speaking at all (nonverbal) to only using a few words
• Walking difficulties, such as clumsiness and a wide-based walk
• Difficulty with balance or coordination (ataxia)
• Increased muscle tone in their arms and legs or decreased muscle tone in their trunk
• Seizures
• A small head with a short and broad skull
• A wide mouth and a big lower jaw
• A large tongue and widely spaced teeth

Facial features may be more apparent in adults with Angelman syndrome.

Other symptoms may include:

• Difficulty feeding
• Sleep disturbances
• Constipation or gastroesophageal reflux disorder (GERD)
• Eye issues, like involuntary eye movements, crossed eyes or sensitivity to light
• Skin discoloration (hypopigmentation)

Angelman syndrome causes

A genetic variant of the UBE3A gene causes Angelman syndrome. This gene tells your body to make an enzyme that helps your nervous system work. Any loss or damage to this gene causes symptoms of Angelman syndrome.

You inherit one copy of the UBE3A gene from each biological parent. Both copies are “turned on” (active) in most tissues. But in parts of your brain, only the maternal copy works. If the maternal copy of the UBE3A gene is lost or damaged for any reason, you’ll have no active copies of the gene in some parts of your brain. This can affect how your nervous system functions.

Some cases of Angelman syndrome may be the result of a gene change that researchers haven’t found yet.

You can’t prevent Angelman syndrome because it happens due to random genetic changes during fetal development. In most cases, this happens without a known cause.

Complications of this condition

Complications of Angelman syndrome may include:

• Growth issues due to trouble feeding, especially in infants
• Physical injuries due to seizures and falls
• Spine curvature (scoliosis)

Your child’s healthcare team can help prevent or manage these issues.

How doctors diagnose this condition

Healthcare providers look for the characteristic signs and symptoms of Angelman syndrome to make a diagnosis. But these signs aren’t usually apparent at birth. Providers usually diagnose it between ages 1 and 4. They can sometimes identify the condition during pregnancy.

Noninvasive prenatal screening (NIPS) may detect Angelman syndrome before birth. NIPS is a method of determining the risk that your baby will be born with certain genetic conditions. This test analyzes small fragments of DNA that are in a pregnant woman’s blood.

If there’s no diagnosis during pregnancy, developmental delays are often the first sign that leads to a diagnosis. Examples of missed developmental milestones include not saying their first words or not taking their first steps as expected. Your child’s provider will also look for common symptoms or characteristics of the condition.

Testing confirms a diagnosis. Your child’s provider may offer genetic testing that identifies changes to the UBE3A gene. Your child may need other tests to rule out conditions with similar symptoms.

Misdiagnosis is possible. This is because Angelman syndrome symptoms closely resemble those of other conditions, like:

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

Genetic testing and other tests are very important to make an accurate diagnosis.

How is it treated?

There’s currently no cure for Angelman syndrome. But treatment can help your child manage symptoms. This may include:

• Antiseizure medications
• Communication aids and speech therapy, including sign language, gesturing and using assistive devices
• Early intervention and educational resources to help with developmental milestones and academic goals
• Physical therapy to help with balance, coordination and walking difficulties
• Occupational therapy to help your child gain independence and perform everyday tasks
• Back, ankle or foot braces for support
• Modified feeding methods for infants, like using special bottle nipples
• Good sleep hygiene habits
• Medications to help food move through your child’s gastrointestinal tract

Children with Angelman syndrome will likely need help with daily tasks throughout their lives. Your child’s care team can answer questions and offer support. They also might be able to recommend a local or online support group.

When should my child see their healthcare provider?

Your child will need to see their healthcare team regularly. This is to make sure their treatment and therapies are working. Let their provider know if you notice new or worsening symptoms. Visit the emergency room if your child has a seizure for the first time.

What can I expect if my child has this condition?

Your child’s healthcare provider will consider many factors when evaluating their outlook. You can expect some mobility, speech and developmental delays as they grow. Your child can still play, learn and take part in activities with other kids.

Some adults with the syndrome can live partly on their own, with helpers coming when needed. Others may need more support in assisted living or full-time care facilities.

Life expectancy

Many people with Angelman syndrome have a typical life expectancy. But symptom severity varies. Complications from severe seizures and injuries after falls may be life-threatening. Your child’s care team will offer ways to keep your child safe to prevent these outcomes.