Autism is a neurodevelopmental disorder characterized by impaired social interaction, verbal and non-verbal communication, and by restricted and repetitive behaviour. The diagnostic criteria require that symptoms become apparent before a child is three years old.
Autism has a strong genetic basis; however the genetics of autism are complex and it remains unclear whether ASD is explained more by rare mutations, or by rare combinations of common genetic variants. In rare cases, autism is strongly associated with agents that cause birth defects. The prevalence of autism is 1 in every 110 children and the Centre for Disease Control and Prevention reported, in 2012, that one in 88 American children (one in 54 boys) are on the autism spectrum with a prevalence rate increasing at 17% per year (an increase of which only 50% can be explained by a better diagnosis). This demonstrates the prevalence of ASD and its significance as an urgent public health concern.
Parents usually notice signs in the first two years of their child’s life. The signs usually develop gradually, but some autistic children first develop normally and then regress. Several studies have shown the benefits of early diagnosis and intervention for children with developmental disabilities and, particularly, for those with difficulties on the autism spectrum.