Angelman Syndrome

February 3, 2017

Angelman syndrome is a genetic disorder that affects the nervous system and causes severe physical and intellectual disability. It is a severe neurological disorder characterized by profound developmental delays, problems with motor coordination (ataxia) and balance, and epilepsy. Individuals with AS do not develop functional speech. The seizure disorder in individuals with Angelman Syndrome can be difficult to treat. Feeding disorders in infancy are common, and some persist throughout childhood. Sleeping difficulties are commonly noted in individuals with Angelman Syndrome. AS affects all races and both genders equally.

Children with Angelman syndrome typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping movements. Hyperactivity, a short attention span, and a fascination with water are common. Most affected children also have difficulty sleeping and need less sleep than usual.

With age, people with Angelman syndrome become less excitable, and the sleeping problems tend to improve. However, affected individuals continue to have intellectual disability, severe speech impairment, and seizures throughout their lives. Adults with Angelman syndrome have distinctive facial features that may be described as “coarse.” Other common features include unusually fair skin with light-colored hair and an abnormal side-to-side curvature of the spine (scoliosis). The life expectancy of people with this condition appears to be nearly normal.

Angelman syndrome affects an estimated 1 in 12,000 to 20,000 people.


For the majority of people with AS, the cause is a deletion in chromosome 15.  This is true for about 70% of those diagnosed with AS.  Another five to seven percent have a mutation of the chromosomal region in UBE3A.  Two to three percent have no deletion or mutation, but the person is still missing the active UBE3A gene.  Some have unusual chromosomal rearrangements and for the rest (about 15%), the cause is still unknown.


Angelman syndrome is difficult to detect at birth. Between the ages of 6 and 12 months, developmental delays may become apparent. All individuals with Angelman syndrome have difficulty with speech and movement. Most have abnormal brain activity, seizures, and microcephaly (the circumference of the head is smaller than normal because the brain has not developed properly or has stopped growing).

Characteristic symptoms of Angelman syndrome that are usually present include:

  • Delayed motor development, such as delay in sitting, crawling and walking
  • Speech problems
  • Jerky, puppet-type movements
  • Stiff-legged walking style
  • Hand flapping
  • Hyperactive behaviour
  • Loving, happy and social demeanour
  • A child easily moved to laughter
  • Intellectual disability – a child with Angelman syndrome will have delayed development in all areas and disability is severe in most cases.

Characteristic symptoms of Angelman syndrome that are sometimes present include –

  • Small head
  • Characteristic EEG (brainwave) abnormalities
  • Epilepsy (occurs in 80 per cent of cases).


Complications associated with Angelman syndrome include –

  • Feeding difficulties – An inability to coordinate sucking and swallowing may cause feeding problems during the infant’s early months. Your pediatrician may recommend a high-calorie formula to help your baby gain weight.
  • Hyperactivity – Moving quickly from one activity to another, short attention span, and keeping hands or a toy in their mouths may characterize children with Angelman syndrome. Hyperactivity often decreases with age, and medication usually isn’t necessary.
  • Sleep disorders – People with Angelman syndrome often have abnormal sleep-wake patterns and need less sleep than normal. In some cases, sleep difficulties may improve with age. Medication and behavior therapy may help control sleep disorders.
  • Curving of the spine (scoliosis) – Some people with Angelman syndrome develop an abnormal side-to-side spinal curvature over time.
  • Obesity – Older children with Angelman syndrome tend to have large appetites, which may lead to obesity.


  • Anti-seizure medication to control seizures
  • Physical therapy to help with walking and movement problems
  • Communication therapy, which may include sign language and picture communication
  • Behavior therapy to help overcome hyperactivity and a short attention span and to aid in development

Alternative treatment

Speech-language therapy – Individuals with Angelman syndrome may benefit from speech-language therapy. During speech-language therapy, a qualified speech-language professional (SLP) works with the patient on a one-to-one basis, in a small group, or in a classroom to overcome speech and language problems. Programs are tailored to the patient’s individual needs. On average, patients receive five or more hours of therapy per week for three months to several years. Speech pathologists use a variety of exercises to improve the patient’s communication skills, with a focus on nonverbal communication for patients with Angelman syndrome.

Occupational therapy – Patients with moderate-to-severe intellectual disabilities may benefit from occupational therapy. During sessions, a therapist helps the child learn skills to help him or her perform basic daily tasks, such as feeding, dressing, and communicating with others.

Ketogenic diet – A ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet used to treat some forms of epilepsy in children. The diet mimics aspects of starvation by forcing the body to burn fat rather than carbohydrate stores. Normally, the carbohydrates in food are converted into glucose, which is then transported around the body and is particularly important in fueling the brain.