Angelman Syndrome

Angelman syndrome facts*

*Angelman syndrome facts Medically Edited by:

  • Angelman syndrome is a genetic disorder with characteristic features that include severe speech impairment, developmental delay, intellectual disability, and ataxia (problems with movement and balance).
  • Angelman syndrome is named after the physician Harry Angelman who first delineated the syndrome in 1965.
  • Angelman syndrome affects an estimated 1 in 12,000 to 20,000 people.
  • Most children with Angelman syndrome have microcephaly (small head size) and epilepsy (recurrent seizures).
  • The developmental delay of Angelman syndrome generally becomes noticeable by the age of 6 to 12 months.
  • Adults with Angelman syndrome have facial features that are distinct and are often described as "coarse."
  • Some of the characteristic features of Angelman syndrome are a result from the loss of function of a gene called UBE3A.
  • The life expectancy for individuals with Angelman syndrome appears to be nearly normal.

What is Angelman Syndrome?

Angelman syndrome is a genetic disorder that causes developmental delay and neurological problems. The physician Harry Angelman first delineated the syndrome in 1965, when he described several children in his practice as having "flat heads, jerky movements, protruding tongues, and bouts of laughter."

What are the characteristics, signs, and symptoms of Angelman syndrome?

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  • Infants with Angelman syndrome appear normal at birth, but often have feeding problems in the first months of life and exhibit noticeable developmental delays by 6 to 12 months.
  • Seizures often begin between 2 and 3 years of age.
  • Speech impairment is pronounced, with little to no use of words. Individuals with this syndrome often display hyperactivity, small head size,sleep disorders, and movement and balance disorders that can cause severe functional deficits.

Angelman syndrome results from absence of a functional copy of the UBE3A gene inherited from the mother.

Medically Reviewed by a Doctor on 4/1/2014

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