Autism is a developmental brain disorder that is usually identified in children by the age of three.
The incidence of autism has jumped from one in 2,000 to the current figure of one in 166 in just one generation, making it the world's fastest growing disability.
The exact cause of autism is not known, but boys are four times more likely to be affected than girls.
Autism affects social interaction and communication, but the characteristics differ from child to child.
Autistic children may have little or no speech, but can also be quite verbal and repeat certain words or make meaningless statements.
The child may also find it difficult to form relationships, and spend a lot of time alone.
Autistic children dislike change and their play patterns may be very repetitive and unimaginative.
Autistic children are also affected by sensory problems. They can appear deaf at times or be panicked by certain sounds. They may also behave self-destructively, hitting their head or torso and flapping their arms.
Hélène Hofman