A disorder that stops people walking and speaking
The disorder is believed to affect between 1 in 12,000 and 1 in 24,000 people, although these statistics may be underestimated. Many cases of Angelman syndrome may remain undiagnosed because the symptoms and characteristics of the disorder resemble those of other conditions. Men and women are equally likely to experience this disorder.
Cause: Angelman syndrome is a genetic disorder named after Dr. Harry Angelman, who first reported it in 1965. The disorder primarily affects the central nervous system, i.e. the brain and spinal cord, and is caused by mutations in the UBE3A gene. This gene provides instructions for proteins needed to maintain the normal growth and function of cells, including neurons in the brain.
In each cell, humans usually have 23 pairs of chromosomes — thread-like structures that contain DNA. One parent contributes half of each chromosome pair, and the other parent contributes the other half. UBE3A is located on chromosome 15. Mutations that delete a gene or change its structure, function, or activity can cause Angelman syndrome. In many cases, a mutation develops spontaneously on the copy of the gene from the mother.
The genetic mutations behind Angelman syndrome usually occur randomly, but 3% to 5% of children inherit it from their parents. In about 10% of people with this condition, the exact cause of the syndrome cannot be identified.
People with Angelman syndrome usually begin to develop symptoms of the disorder in early childhood. These include developmental problems, such as difficulty sitting without support or babbling, which become apparent around 6 to 12 months of age.
As the disorder progresses, affected people may have difficulty speaking and walking because of balance and coordination problems. They may also have seizures, which usually begin when the child is 2 to 3 years old. In addition, some people with this condition may have distinctive facial features, such as a prominent chin, deep-set eyes or an unusually wide mouth. People who have this syndrome usually have a normal life expectancy.
The symptoms of Angelman syndrome can sometimes be confused with other disorders that cause developmental delays, such as autism or cerebral palsy, which can possibly lead to misdiagnosis.
There is currently no cure for Angelman syndrome.
However, a number of treatment options exist to help manage their symptoms. For example, doctors may prescribe anti-epileptic medications to control patients’ seizures. Physiotherapy and communication therapy can also help improve patients’ ability to walk and communicate with others without speaking – for example, by using hand gestures or signs.