First identified by the British physician and pediatrician Harry Angelman in 1965, Angelman syndrome is a relatively rare genetic disorder and estimated to affect approximately 1 in 12,000 to 20,000 people around the world.
It is most commonly caused by deletion of the chromosome fifteen or by other irregularities relating to the same chromosome. Genetic mutation can also lead to Angelman syndrome during early development of the embryo or even at the point of egg fertilization. In most cases the condition is not passed down from the parents but is the result of a chance genetic event.
Infants will not usually show any signs of Angelman syndrome until they reach the age of 6 to 12 months when developmental milestones begin to become delayed, such as being unable to sit whilst unsupported or able to make babbling sounds. It is common for seizures to begin when the child reaches 2 to 3 years old. Some children may also have microcephaly resulting in developing of an unusually small head or flatness at the back of the head.
In the past Angelman syndrome has been known as happy puppet syndrome due to the persons excitable nature, their frequent laughter and smiling as well as having distinctive jerky physical movements often with hands flapping. Other symptoms include speech impairment, sleep problems, a short attention span and often fascination with water.
Some individuals with Angelman syndrome may develop certain physical characteristics such as a wide mouth, wide teeth spacing, a habit of sticking out their tongue, crossed eyes and occasionally a curvature of the spine.
Those with Angelman syndrome have a normal life expectancy and whilst there is no specific therapy for the condition itself, quality of life can be greatly improved. Physical, occupational, communication and behavioural therapy can all help the person to achieve their maximum potential. Aside from seizures, those with the condition usually have good general health.
With maturity people with Angelman syndrome often become less excitable and any sleeping problems generally improve. It is usual for intellectual disability to continue into adulthood and speech often remains limited or difficult. The symptom of seizures commonly remains and some adults find that joints may become stiffer.
Throughout adult life general regression is not common and it is rare for any symptoms of Angelman syndrome to become more pronounced with age. With experience and maturity people affected are often able to continue improving their communication abilities as well as developing new skills during the course of their lives.
Due to the nature of many of the symptoms, people with Angelman syndrome may find it hard or even dangerous to navigate the outside world as they struggle to understand events occurring around them or have trouble communicating themselves to others clearly. Fascination with water can also create a risk factor with drowning.
Genetic research into Angelman syndrome is ongoing with some promising early results. It is the belief of some scientists that in the future there will be a genetic procedure available that will aid treatment of the condition.