Overview of Autism Spectrum Disorders

Although autism has a strong genetic basis, it is unclear whether it is caused by a genetic mutation or genetic recombination. Some genetic problems affect brain development, while others affect the severity of symptoms. Some genetic problems seem to be inherited, while others are spontaneous, so it is hard to pinpoint an exact genetic cause for Autism.
             Environmental factors have been linked to Autism, although there is no solid evidence as to whether or not they are a direct cause of ASD. These factors include certain foods, disease, heavy metals and solvents, air pollution, and pesticides. Smoking and illicit drug use during pregnancy have also been said to have a role in causing ASD, but no reliable research studies on that have been published to date, although extensive studies are underway. (2).
             There are some risk factors associated with Autism. Boys are more inclined to have ASD than girls are. Family history also plays a role in the disease; parents of one autistic child have a greater risk of having another affected child. Also relatives of autistic people are more likely to have an autistic child, but the cause for this is unclear. Children with certain medical disorders have a higher than normal risk of being affected by autism. These conditions include fragile X syndrome, tuberculosis syndrome, Tourette's syndrome and epilepsy. (3) There may also be a connection between the parents' ages and the incidence of autism, with older parents running a greater risk of having an autistic child than younger parents, but more research is necessary to prove this. A small percentage of children with low birth weight or who are born prematurely are at a greater risk of having autism. (4).
             The symptoms of autism cover a wide range of behaviors and deficiencies. Most children show signs of autism during infancy, although some may develop like normal children and then suddenly show signs of the disease.