Razi Journal of Medical Sciences

Background: Autism Spectrum Disorder (ASD) is a devastating, developmental disease and has several significant impacts on the patient’s life: impairment in social interactions as in both verbal and nonverbal behaviors, failing to develop relationships and respond to normal teaching methods, intellectual disabilities, and repetitive behaviors, being unable to instinctively express natural empathy, pragmatic language impairment and severely limited activities.

The prevalence of ASD has increased in children globally including our country. Latest studies conclude that ASD affects boys four to five times more than girls and the average age of initial diagnosis is often before the age of 3 years.

ASD is a multifactorial disorder and studies so far indicate a strong genetic basis for its development, showing the cause for more than 90% of brain function disorders and autistic behavior to be of genetic roots. However, genetics only do not consider for all cases of autism. Environmental factors are crucial issues in the development of autistic behaviors for example, prenatal exposure to the chemicals, low levels of vitamins especially vitamin D, stress, maternal depression or antidepressant use, advanced paternal age, exposure to air pollutants and pesticides, parental obesity and diabetes in the mother during pregnancy, live in crowded infected in the brains, has been linked to increased risk of autism.

In this review, we discussed the definition and prevalence of ASD immune dysfunctions and genetic factors in autism.

According to the previously studies, environmental factors alone cannot cause autistic behavior in children, but genetics and environmental factor can converge to causes disease with neurological problems and may cause abnormal autistic behaviors in children. However environmental factor can affect genetic and epigenetic in the parents that this event created a prominent role of environmental factors in autism spectrum disorders.