What is Angelman Syndrome?

What is Angelman Syndrome?

Angelman Syndrome is a neuro-genetic disorder that is often misdiagnosed as autism or cerebral palsy. Symptoms include developmental delay, seizures, lack of speech, and motor disorders. Named after Dr. Harry Angelman, who first noted and described the symptoms, Angelman Syndrome does feature many of the same characteristics of other developmental disabilities, but it has a certain genetic component that distinguishes it from other disorders.

Angelman Syndrome is connected with the number 15 chromosome. Most often, a portion of this chromosome is deleted, which results in Angelman Syndrome. Other genetic causes include two paternally derived number 15 chromosomes, a mutation, or imprinting center deficit. These causes can be screened through a DNA laboratory.

While normal pre-natal and birth history is present, by 6 to 12 months of age, a child can begin showing signs of Angelman Syndrome. Developmental delays such as unsteady limb movement or increased smiling are evident. As a child develops, common symptoms of Angelman Syndrome include:

  • Severe developmental delays
  • Movement or balance disorder — ataxia or awkward gait, unsteadiness, jerky limbs
  • Speech impairment — few or no words, receptive and non-verbal communication more advanced than verbal
  • Excitable personality — frequent smiling or laughter, general happy disposition, hypermotoric behavior

Other symptoms seen frequently include delayed or disproportionate head circumference or microcephaly, seizures usually onset before 3 years of age, and abnormal EEG. Other possible signs include protruding tongue, frequent drooling, wide mouth, wide spaced teeth, abnormal sleep-wake cycles, fascination with water, increased sensitivity to heat, and abnormal food-related behaviors.

Angelman Syndrome occurs about one in every 15,000 births. Notable cases include sons of actor Colin Farrell and author Ian Rankin.

The clinical features of Angelman Syndrome alter with age, and prognosis depends on the severity of each case. Some children with Angelman Syndrome will require life-long care. It is not a degenerative disorder, so many individuals can improve with support.

Visit angelman.org for upcoming events and more information about Angelman Syndrome.

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