Autism, or Autism Spectrum Disorder (ASD), is a developmental disorder that appears in early childhood. The term ASD is used to describe a group of conditions where there are deficits in communication, social interactions, and restricted repetitive behaviors. It includes many disorders that have previously been called Rett syndrome, Asperger syndrome, fragile X syndrome, pervasive developmental disorder, and autistic disorder.
Before classified as part of ASD, Asperger syndrome was used to describe high-functioning individuals who have normal or superior intellectual abilities with ASD. Fragile X and Rett syndrome are genetic conditions that may exhibit traits of ASD. Many techniques have been developed to help individuals with ASD to achieve good outcomes in terms of education and occupation.
The exact mechanism or cause of autism is unknown. However, there are several hypotheses that revolve around obstetric complications, genetic abnormalities, gestational infections, and exposure to toxic agents. Based on genetic studies, experts have found that heritability accounts for 74% to 93% of the risk for ASD. The risk for ASD also increases when the maternal age is above 40, paternal age more than 50, and having intervals between pregnancy of less than 24 months. Other factors include maternal rubella and tuberous sclerosis. There are also some reports that have linked vaccinations with autism; however, these findings were not supported by broader research. Research from the CDC and another case control study reported no increased risk between vaccinations and ASD development. Full immunization of children should be encouraged.