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5 July, 2009

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Angelman syndrome

Angelman syndrome is a genetic condition that is present at birth (congenital). It causes intellectual disability and other features. Other characteristics of Angelman syndrome include distinctive facial features, mental retardation, speech problems and hyperactive behaviour. In most cases, the cause is a missing section (deletion) on the mother’s copy of chromosome 15.

This condition was once known as ‘happy puppet syndrome’ because of the child’s sunny outlook and jerky movements. It is now called Angelman syndrome after Harry Angelman, the doctor who first investigated the symptoms in 1965.

Most diagnoses are made between the ages of three and seven years of age. Estimates vary, but Angelman syndrome is thought to affect one child in every 10,000 to 25,000.

Symptoms that are usually present
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.

Symptoms that are sometimes present
Characteristic symptoms of Angelman syndrome that are sometimes present include:

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

Characteristic physical features
The characteristic physical features of this condition are not always obvious at birth but evolve during childhood. Characteristic physical features of Angelman syndrome include:

Flattened back of the head
Deep-set eyes
Wide, ever-smiling mouth
Prominent jaw and widely spaced teeth
Lightly pigmented hair, skin and eyes.

Typical behaviour problems
Some of the common problems include:

Feeding difficulties
Disturbed sleep
Delayed toilet training (about 80 per cent of adults are dry during the day).

Chromosome disorder
A child inherits two sets of chromosomes – one set from each parent. Angelman syndrome occurs in the following scenarios:

A section of genetic material is missing from the copy of chromosome 15 inherited from the mother. This is the most common scenario.
The child inherits two copies of chromosome 15 from its father and none from its mother. This happens occasionally.
The child may inherit one chromosome 15 from each parent, but the chromosome from the mother works in the same way as the chromosome from the father.
In 20–30 per cent of cases, there is no cause found. Some of these patients have a fault (mutation) in a gene called UBE3A on chromosome 15.

Diagnosis
Diagnosis methods include checking for the clinical features of Angelman syndrome and performing DNA tests.

Angelman syndrome may be mistaken for autism because of similar symptoms including hyperactive behaviour, speech problems and hand flapping. However, a child with Angelman syndrome is highly sociable, unlike a child with autism. It is important that the child is carefully diagnosed, because sometimes Angelman syndrome and autism are both present.

Other conditions that share some common characteristics with Angelman syndrome include Rett syndrome, Lennox-Gastaut syndrome and non-specific cerebral palsy.

Treatment
There is no cure for Angelman syndrome, but the child can benefit from a range of treatments for some symptoms including:

Speech therapy
Behaviour modification
Communication therapy
Occupational therapy
Physical therapy
Special education
Social skills training
Anti-epileptic medication.

Angelman syndrome is not a degenerative disease. Children with Angelman syndrome can expect a normal lifespan.

Support for parents
Support for parents includes:

Support organisations, such as the Australian Angelman Syndrome Association
Genetic counselling
Family therapy
Respite care.

Where to get help

Your doctor
Australian Angelman Syndrome Association www.angelmansyndrome.org
Autism Victoria Tel. (03) 9885 0533
The Centre for Developmental Disability Health Victoria (CDDHV) Tel. (03) 9564 7511

Things to remember

Angelman syndrome is a neurological disorder caused by a missing section of chromosome 15.
Common characteristics include intellectual disability, delayed speech or no speech at all, jerky walking style and happy demeanour.
There is no cure, but the child can benefit from treatment including physical therapy, special education and behaviour modification.

You might also be interested in:
Autism.
Autism - suggestions for parents.
Disability - support services.
Genes and genetics.
Genetic services in Victoria.

Want to know more?
Go to More information for support groups, related links and references.

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