Angelman Syndrome: Meaning, Causes, Symptoms, Treatment

Written by Medicover Team and Medically Reviewed by Dr Purva Shripal Jain , pediatrician

Angelman Syndrome is a rare genetic and neurological disorder that mainly affects the nervous system. It causes serious developmental delays, speech impairment, movement difficulties and unique behavioural traits such as frequent smiling, laughter and an excitable personality.

The condition is caused by problems with the UBE3A gene located on chromosome 15. Angelman syndrome is a rare condition and affects approximately 1 in 12,000 to 20,000 people worldwide. Symptoms usually appear in early childhood and while there is no cure, treatments and therapies can greatly improve the quality of life.

What are the Causes of Angelman Syndrome?

Angelman syndrome develops due to different genetic changes that affect how the UBE3A gene on chromosome 15 functions. Some of the common causes of Angelman syndrome are:

Maternal deletion on chromosome 15: In this case, a small portion of the mother's chromosome 15 is missing, which normally carries the active UBE3A gene. The brain cannot use the gene properly without this copy.
UBE3A gene mutation: In some cases, the maternal copy of chromosome 15 is present but the UBE3A gene itself is faulty due to a mutation. This prevents the gene from producing the protein it normally makes.
Paternal uniparental disomy (UPD): Here, instead of receiving one chromosome 15 from the mother and one from the father, the child receives both copies from the father. Since the paternal copy of UBE3A is usually inactive in the brain, the gene does not function.
Imprinting defects: Sometimes the maternal copy of chromosome 15 is present but not properly active due to imprinting errors. This means the gene is silent and the body cannot use it.

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Angelman Syndrome Symptoms

The symptoms of Angelman syndrome usually become noticeable between 6 months and 2 years of age, as developmental delays and unusual behaviours emerge. Here are some common signs of Angelman syndrome:

Developmental delays: Babies may take more time to roll, crawl, walk or sit compared to peers. Learning new skills remains slow throughout life.
Severe speech impairment: Most children speak very few words and their ability to understand language is usually stronger than their ability to express it.
Movement and balance problems: Many children have ataxia, tremors, stiff movements and jerky motions. These may make walking more difficult but can be improved with therapy.
Frequent smiling and laughter: A hallmark feature of Angelman syndrome is the constant happy appearance with frequent laughing, smiling and excitability. Because of these unique traits, it is also called as happy puppet syndrome.
Hyperactivity and short attention span: Children may move constantly, have difficulty focusing and may display hand-flapping or other repetitive movements.
Sleep disturbances: Difficulty falling asleep and frequent nighttime waking are common. Some children gradually improve with age but many need medical support for sleep.
Seizures: Around 80 to 90% of children develop seizures and the first seizure starts between 2 and 3 years of age. These require long-term medical treatment and care.
Distinctive physical features: Many children have a small head size (microcephaly), wide mouth, protruding tongue, prominent chin and sometimes light-colored skin, hair or eyes.

Characteristics and Features of Angelman Syndrome

Children and adults with Angelman syndrome share a unique combination of physical, developmental and behavioural features that help doctors recognise the condition early. These features usually appear in infancy or early childhood and continue into adulthood, although their intensity may change over time.

Frequent smiling, laughter and an overall cheerful appearance are the main signs of Angelman syndrome.
Sitting, crawling and walking may be delayed and usually seen with unsteady or jerky movements.
Many people have very limited spoken words but their ability to understand language and communicate through gestures, facial expressions or communication devices is stronger.
Many children develop seizures between the ages of 2 and 3 and can be confirmed by an abnormal EEG.
Difficulty falling asleep and frequent waking at night are common. Sleep may improve with age but requires medical or behavioural management.
Poor muscle tone (hypotonia) can cause difficulties with feeding, sucking and swallowing during early development.
Features such as a small head size (microcephaly), wide mouth, prominent chin and protruding tongue may be present.

Hyperactivity and restlessness are common.
Children may find it difficult to focus on a specific tasks for long periods.
Hand-flapping, jerky motions and unusual body postures often occur.
Impulsivity and lack of danger awareness.
Many children show a strong attraction to water activities or shiny objects.
Daytime irritability due to poor sleep.

Risks or Complications of Angelman Syndrome

If Angelman syndrome is not treated on time, it can cause several health and developmental problems in children. These complications may differ in severity from one child to another but they usually affect both daily life and children's health.

Seizures: Many children with Angelman syndrome experience recurrent seizures, which require lifelong medicines and regular neurological monitoring.
Sleep disturbances: Frequent sleep problems can interfere with learning, behavior and overall development, which can result in excessive daytime fatigue.
Feeding and nutrition issues: Infants with low muscle tone may struggle with sucking or swallowing, which can result in poor weight gain or malnutrition if not addressed early.
Movement-related risks: Poor balance, stiff or jerky walking and coordination difficulties increase the risk of falls and injuries.
Communication difficulties: Limited speech abilities may cause frustration, emotional outbursts or behavioural problems when children cannot express their needs effectively.

When to See a Doctor

Parents should consult a doctor if their child shows the following symptoms:

Delayed developmental problems like not sitting, crawling or walking at the expected age.
Lack of speech or very limited speech development.
Seizures or abnormal movements.
Persistent sleep problems.
Unusual behavioural patterns like excessive laughter or hand-flapping.

Diagnosis of Angelman Syndrome

Diagnosing Angelman syndrome begins when a child shows signs such as developmental delay, limited speech, unusual behaviour or frequent laughter. Since these symptoms may overlap with other neurological conditions, doctors use several clinical observations and genetic tests to confirm the condition.

Clinical evaluation: Doctors first assess the child's growth, developmental and behavioural traits. Features such as delayed motor skills, speech difficulties, movement problems and a happy, excitable personality may raise suspicion of Angelman syndrome.
Genetic testing:

DNA methylation testing is the most common initial test. It can detect around 80% of Angelman cases by identifying missing genetic information or imprinting errors on chromosome 15.
If methylation testing is normal, UBE3A gene sequencing may be done to look for specific mutations that affect the gene's function.

EEG (electroencephalogram): Many children with Angelman syndrome show distinctive brain wave patterns, even before seizures begin. This test can provide supporting evidence for diagnosis.
Imaging tests: A brain MRI is sometimes recommended to find out other neurological conditions, although it usually appears normal in children with Angelman syndrome.

Management and Treatment of Angelman Syndrome

There is no permanent cure for Angelman syndrome but with the right medical care, therapies and lifestyle, children can achieve steady development and live healthier, happier lives. The management plan involves the following:

1. Therapies

Therapies are an essential part of managing Angelman syndrome and should begin as early as possible:

Speech and communication therapy: Since speech is very limited, children are taught to communicate through sign language, picture boards and digital communication devices.
Occupational therapy: This therapy helps children develop independence by improving fine motor skills, hand-eye coordination and daily self-care activities such as dressing and eating.
Physical therapy: This therapy is used to Improves balance, posture and walking ability, while also reducing the risk of falls and muscle stiffness.
Behavioural therapy: It focuses on managing hyperactivity, short attention span and sleep-related challenges using proper routines and coping strategies.

2. Angelman Syndrome Treatment

Some children require medical treatments to address specific health concerns:

Anti-seizure medicines are prescribed to manage epilepsy, which is common in Angelman syndrome.
Melatonin or other sleep medications may be recommended to help regulate disrupted sleep cycles.
Feeding and nutrition support is important for infants with low muscle tone who may struggle with sucking, swallowing or weight gain.

3. Lifestyle and Educational Support

Planned daily routines help reduce restlessness, improve behaviour and support better sleep.
Special education programs tailored to a child's learning ability ensure steady progress in academics and skills.
Parental counselling and support groups provide families with guidance, emotional support and coping strategies to manage daily challenges.

Angelman Syndrome Prognosis

Angelman syndrome is a rare and lifelong condition but with proper treatment and care, most children can grow into adulthood and enjoy successful lives. The level of independence depends on the severity of symptoms and the type of support they receive.

Learning and daily activities: Most children require lifelong support for learning, communication and daily living skills and can also participate in social and recreational activities with support.
Angelman syndrome life expectancy: People with Angelman syndrome generally have a normal lifespan, provided seizures and other medical complications are well managed.
Quality of life: With early therapies, seizure control, sleep plan and strong family support, children can develop social connections, enjoy interactions and lead happy lives.

Conclusion

Angelman Syndrome is a rare but manageable genetic condition that affects the development, communication and behaviour of children. While there is no cure but early diagnosis, therapies, medical treatments and strong family support can greatly improve the quality of life for affected children and adults.

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