Autism spectrum disorder
The exact cause of autism spectrum disorder (ASD) is currently unknown.
It's a complex condition and may occur as a result of genetic predisposition (a natural tendency), environmental or unknown factors.
Most researchers believe that certain genes a child inherits from their parents could make them more vulnerable to developing ASD.
Cases of ASD have been known to run in families. For example, younger siblings of children with ASD can also develop the condition, and it's common for identical twins to both develop ASD.
No specific genes linked to ASD have been identified, but it may be a presenting feature of some rare genetic syndromes, including Fragile X syndrome, Williams syndrome and Angelman syndrome .
Some researchers believe that a person born with agenetic vulnerability to ASD only develops the condition if they're exposed to a specific environmental trigger.
Possibletriggers include being born prematurely (before 35 weeks of pregnancy), or being exposed in the wombto alcohol or to certain medication, such as sodium valproate (sometimes used to treat epilepsy during pregnancy).
No conclusive evidence has been found linking pollution or maternal infections in pregnancy with an increased risk of ASD.
Below are some other conditions known to be associated with ASD:
The characteristics of autistic spectrum disorder (ASD) can vary both from person to person and across different environments. They can also be different for the same person at different times in their life.
Autism spectrum disorder (ASD) is a condition that affects social interaction, communication, interests and behavior. There's no "cure" for ASD, but speech and language therapy, occupational therapy, educational support and other interventions.
The main features of autism spectrum disorder (ASD) are problems with social communication and interaction. Signs of ASD include: frequent repetition of set words and phrases, speech that sounds very monotonous or flat, preferring to communicate using single words, despite being able to speak in sentences, etc.
The exact cause of autism spectrum disorder (ASD) is currently unknown. It's a complex condition and may occur as a result of genetic predisposition (a natural tendency), environmental or unknown factors.
See your GP or health visitor if your child is showing symptoms of autism spectrum disorder (ASD), or you're worried about their development. Some people with ASD grow up without their condition being recognised, but it's never too late to get a diagnosis.
There's no 'cure' for autism spectrum disorder (ASD). However, a range of specialist educational and behavioural programmes can help children with ASD.
Adults with ASD may also benefit from some of the treatments offered to children with ASD, such as psychological therapy and medication. Adults with ASD can live in all types of housing.
Daniel Weston, who has autism, experienced a transformation since taking up tandem cycling with his dad, Pat. "Daniels major impairment is social and communications skills, which affects his life drastically," says his mother.
Sarah Ridout lives in Exeter. At the age of 23, she was diagnosed with Asperger syndrome, a condition on the autistic spectrum. "I'm passionate about raising awareness, particularly within the police force. I'm a member of the force's Disability Forum." she says.
Aly Gynn was diagnosed with Asperger syndrome, a disorder on the autistic spectrum, at the age of 45, although he had suspected for some time that he had the condition.