Angelman syndrome

Angelman syndrome is a genetic disorder that causes developmental disabilities and neurological problems, such as difficulty speaking, balancing and walking, and, in some cases, seizures. Frequent smiles and outbursts of laughter are common for people with Angelman syndrome, and many have happy, excitable personalities.

Angelman syndrome usually isn't detected until parents begin to notice developmental delays when a baby is about 6 to 12 months old. Seizures often begin when a child is between 2 and 3 years old.

People with Angelman syndrome tend to live a normal life span. But they may become less excitable and develop sleep problems that may improve with age. Treatment focuses on managing medical and developmental issues.

Symptoms Causes Risk factors Complications Prevention

Characteristic Angelman syndrome signs and symptoms include:

  • Developmental delays, such as lack of crawling or babbling at 6 to 12 months, and intellectual disability
  • Lack of or minimal speech
  • Inability to walk, move or balance well (ataxia)
  • Frequent smiling and laughter
  • Happy, excitable personality

People who have Angelman syndrome may also have other signs and symptoms, including:

  • Seizures, usually beginning between 2 and 3 years of age
  • Stiff or jerky movements
  • Small head size, with flatness in the back of the head (microbrachycephaly)
  • Tongue thrusting
  • Light pigmentation in hair, skin and eyes (hypopigmentation)
  • Unusual behaviors, such as hand flapping and arms uplifted while walking

When to see a doctor

Most babies with Angelman syndrome don't show signs or symptoms of the disorder when they're born. The first signs of Angelman syndrome are usually developmental delays, such as lack of crawling or babbling, between 6 and 12 months.

If your child seems to have developmental delays or if your child has other signs or symptoms of Angelman syndrome, make an appointment with your child's doctor.

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