Traits & Symptoms of Angelman Syndrome
Every individual living with Angelman syndrome is unique, but many share developmental, physical, and behavioral characteristics. These traits and symptoms can vary in severity and change over time.
Recognizing them can help families and healthcare providers determine when further evaluation may be needed.
Early signs of Angelman syndrome in babies
Angelman syndrome symptoms in babies typically become noticeable within the first year of life. While pregnancy, birth, and the newborn period are usually unremarkable, developmental delays typically start by 6 to 12 months of age, leading caregivers to seek further evaluation.
Development and Milestones
- Delays in milestones such as sitting, crawling, or babbling
- Typical birth weight and size
- No major birth defects
Other Early Signs
- Low muscle tone (hypotonia)
- Feeding challenges, including reflux or difficulty sucking and swallowing
- Pale eye, skin, and hair color compared to family background (most often seen in those living with Deletion AS)
Signs and symptoms of Angelman syndrome in children
As children grow, additional symptoms and physical characteristics of Angelman syndrome may become more apparent.
Communication
- Severe speech impairment (limited or no spoken words)
- Nonverbal and receptive communication abilities may be stronger than speaking abilities
- Communication can include gestures, signs, facial expressions, picture boards, devices, and other forms of AAC
Movement
- Challenges with balance and coordination (ataxia) that can affect walking and using the hands
- An unsteady or wide-based gait
Seizures
- Seizures, often beginning before age 3
- Can be variable in frequency or type of seizure
- Often controlled with medication
Physical Health
- Constipation and other gastrointestinal issues
- Scoliosis and other orthopedic concerns
- Small head size for the body size (microcephaly)
Sleep
- Difficulty falling or staying asleep
- Frequent night awakenings
- Need for less sleep, overall
Behaviors
- Frequent smiling and laughter, happy demeanor, and excitability
- Hyperactivity or a short attention span
- Fascination with water
Learning
- Delayed development of milestones like walking
- Continued need for assistance with daily activities
Vision
- Strabismus (eye crossing)
- Lazy eye, or other vision problems
- Cortical visual impairment
Common Angelman syndrome symptoms in adults
Individuals living with AS continue to experience developmental and physical challenges into adulthood, and symptoms may evolve over time. Some common Angelman syndrome symptoms in adults include:
- Improved hyperactivity but persistent movement difficulties
- Continued need for assistance with daily activities
- Nonverbal or limited verbal communication
- Ongoing sleep disturbances, though they may lessen with age
- Seizures may improve but often require lifelong management
- Increased risk of mobility issues, including joint problems and scoliosis progression
When to seek an evaluation
Developmental delay can have many causes. If you notice delays, loss of skills, seizures, feeding concerns, or other developmental differences, speak with your child’s primary care provider.
Your provider may refer you to a neurologist, geneticist, or other specialist for further evaluation. Because Angelman syndrome can share traits with other conditions, genetic testing is needed to confirm a diagnosis.
Continue Learning
Learn about the genetic differences that can cause Angelman syndrome.
Understand how Angelman syndrome is diagnosed and the testing that may be needed.
Find trusted information, practical guidance, and ways to connect with the Angelman syndrome community.