Raser

Autism

Autism is a disorder of neural development characterized by impaired social interaction and communication, and by restricted and repetitive behavior.These signs all begin before a child is three years old. Autism affects information processing in the brain by altering how nerve cells and their synapses connectand organize; how this occurs is not well understood. The two other autism spectrum disorders (ASD) are Asperger syndrome, wich lacks delays in cognitivedevelopment and language, and PDD-NOS, diagnosed when full criteria for the other two disordere are not met.

Autism has a strong genetic basis, although the geneticsof autism are complex and it is unclear whether ASD is explained more by rare mutations, or by rara combinations of common genetic variants. In rare cases, autismis strongly associated with agents that cause a birth defects. Controversies surround other proposed environmental causes, such as heavy metals, pesticides orchildhood vaccines; the vaccine hypotheses are biologically implausible and lack convincing scientific evidence. The prevalence of autism is about 1-2 per 1,000people; the prevalence of ASD is about 6 per 1,000, with about four times as many males as females. The number of people diagnosed with autism has increaseddramatically since the 1980s, partly due to changes in diagnostic practice; tue question of whether actual prevalence has increased is unresolved.

Parents usuallynotice signs in the first two years of their child’s life. The signs usually develop gradually, but some autistic children first develop more normally and then regress.