Angelman Syndrome: Definition, Symptoms, And Causes

Angelman syndrome is a rare genetic disorder that is characterized by severe intellectual and motor impairment. The disease equally affects both sexes and occurs in one in every 12,000-20,000 births.

Angelman Syndrome: Definition, Symptoms, And Causes
Angelman Syndrome: Definition, Symptoms, And Causes

Angelman syndrome is of genetic origin and causes serious brain and motor dysfunction. People affected by this syndrome experience a severe delay in psychomotor development with symptoms including a lack of language skills, balance and sleep disturbances, epilepsy, and excessive cheeriness.

Discover our latest podcast

Even if in adulthood some patients display autonomy when going about daily activities, the ability to be completely autonomous is very limited and the patient will have to be cared for and accompanied all their life.


The symptoms of Angelman syndrome are absent at birth and are hard to identify before the age of one. Signs of the disease begin to show themselves between the ages of one and three. Observable symptoms include difficulty sitting and walking, as well as an intellectual disability that manifests itself through an inability to memorize things and severe language disorders, usually first observed through sounds such as babbling.

Although symptoms of Angelman syndrome vary from one individual to another, some are found in all who suffer from the disorder. This includes delayed motor development, hyperactivity, and language that is limited to just a few words. Short attention spans, a stiff and jerky gait, hyperexcitability, and smiling and laughing for no particular reason are other symptoms commonly found in all individuals with Angelman syndrome.

In addition, many patients with Angelman syndrome suffer from epilepsy, hand tremors, sleep disturbances, and eating disorders. In 50% of cases, sufferers have distinctive facial features (wide mouth, gap between the upper teeth, thin upper lip), strabismus, scoliosis, and a tendency towards obesity.


In the vast majority of cases, Angelman syndrome is caused by a genetic anomaly of chromosome 15. This is either a mutation of one or more genes, or an absence of some of them. In 90% of cases, a diagnosis of Angelman syndrome can be made through genetic analysis. In 10% of cases, however, no genetic abnormalities were detected.


If a child's development is severely delayed or they display some of the aforementioned characteristics associated with the disorder, it may be suspected that they have Angelman syndrome.

In order to gather an accurate diagnosis, a blood sample will be taken on which a series of genetic tests can be carried out. These tests may include:

-Chromosome analysis

-DNA methylation

-UBE3A gene mutation analysis

-FISH (fluorescence in situ hybridisation)

If a child is found to have Angelman syndrome, specific diagnosis is especially important in order to find out the exact origion of the genetic anomaly that caused the condition. This works to determine any chances of the disorder developing in another child within the family and what this could mean for other members of the family. Most children will be diagnosed between the ages of 18 months and 6 years.


Angelman syndrome cannot be cured. As soon as the diagnosis is made, it is important to treat the patient as soon as possible using a multidisciplinary approach (psychometrician, physiotherapist, occupational therapist, speech therapist). This early care will allow the child to develop skills such as learning how to walk, as well as alternative communication using signs, pictures, and gestures.

Some symptoms, such as epilepsy and hyperactivity, will require medication. For sufferers with sleep disorder, behavioural treatment may be recommended.

Munchhausen Syndrome: Definition, Symptoms, And Causes Munchhausen Syndrome: Definition, Symptoms, And Causes