Angelman syndrome (AS) is a rare genetic disorder that causes developmental delays. Symptoms can develop during infancy and last throughout a person’s life.

This article explores the causes, symptoms, and treatment options that can help manage this condition.

AS is a rare genetic disorder.

It affects the nervous system and causes developmental delays. It has some clinical similarities to conditions that include autism and cerebral palsy, but the cause is very different.

According to the Angelman Syndrome Foundation, AS affects 500,000 people worldwide and occurs in 1 in 15,000 live births. The condition affects males and females equally.

Key symptoms of AS include:

  • speech impairment
  • movement and balance issues
  • seizures
  • a happy, excitable demeanor

The disorder gets its name from Dr. Harry Angelman, a British physician who first identified the set of symptoms in children.

AS is a genetic disorder that occurs when there is a mutation or chromosomal abnormality that stops the UBE3A gene from functioning normally.

People without AS inherit the UBE3A gene from both parents. Both copies of the gene are active in certain parts of a person’s body. Within portions of the brain, the paternal copy is normally silent, while the maternal copy is active.

This allows for normal brain development, including aspects of speech, movement, and learning.

However, people with AS have a problem with the maternal copy of the UBE3A gene, or a gene mutation causes this copy to be lost. For this reason, in people with AS, this gene is not active in some parts of the brain.

These genetic differences occur during fetal development. In 10–15% of people with AS, a problem with a different gene or chromosome triggers the condition.

Symptoms of AS often become noticeable during early childhood. Developmental delays can occur at 0–24 months.

Developmental delays

Developmental delays of AS may include:

  • an inability of the infant or toddler to support their head
  • an inability to pull themselves up to stand
  • a delay in motor skills, such as crawling
  • difficulty sucking or swallowing, which can lead to feeding issues
  • a delay in walking
  • unstable or difficulty balancing

Other symptoms

Other symptoms of AS typically include:

  • intellectual disability
  • speech impairment, which may cause a lack of babbling or cooing in infants, while young children may resort to nonverbal communication
  • difficulty with movement and balance
  • seizures, which may start between 18 months and 3 years of age
  • small head size
  • happy, smiley, and laughing demeanor
  • hand or arm flapping movements
  • easily excitable, which may decrease as a child gets older
  • hyperactivity
  • short attention span
  • great interest in water and shiny objects
  • love of music
  • sleeping problems, which may improve as the child gets older
  • needing less sleep than others their age
  • very fair skin with light-colored hair and eyes compared to family members
  • sensitivity to light due to a lack of eye pigment
  • scoliosis, a sideways curvature of the spine
  • constipation
  • gastroesophageal reflux disorder
  • drooling
  • crossed eyes
  • involuntary rapid eye movements
  • vision problems
  • increased sensitivity to heat

Less common symptoms can also include distinctive facial features, such as:

  • prominent chin
  • deep-set eyes
  • unusually wide mouth
  • protruding tongue
  • widely spaced out teeth
  • abnormally flat back of head

Although some symptoms may improve as a child gets older, many symptoms will last throughout their life. People with AS have a normal life expectancy.

Some people with the condition may experience stiffness in the joints and mobility issues as they get older. Older children and adults with AS may also be at risk of obesity.

AS symptoms can also cause complications. Certain symptoms may increase the risk of injury, such as:

  • seizures
  • walking difficulties
  • balance issues
  • fascination with water

There is currently no cure for AS. However, researchers believe there is a high possibility of discovering an effective treatment, according to the Angelman Syndrome Foundation.

This is because scientists understand what causes AS, and they can successfully reverse the condition in mice studies.

Currently, early treatment can help manage symptoms. The options include:

  • anti-seizure medication
  • behavioral therapy and sleep routines to help manage sleeping problems
  • breastfeeding support, such as special nipples, to help babies suckle
  • upright positioning for feeding and medicines to help digestion
  • physical therapy
  • ankle braces or supports to help walking
  • braces or corrective surgery for severe scoliosis
  • social support
  • speech and occupational therapy
  • picture-based or computer technology to help with communication

Genetic counseling and support groups may also provide families with extra guidance and support.

AS is a genetic disorder that affects development. People may first notice symptoms in children between 0–24 months of age.

There is currently no cure for AS, but researchers believe there is a high chance of finding one in the future.

A range of treatments can help manage symptoms. These may include medications, physical therapy, and speech and occupational therapies.

People with AS will require support throughout their lives, but they can lead long and happy lives.

Several groups and organizations provide a support network for families, fundraising opportunities, and information on the latest research advances.