The Latest on Autism
What Causes Autism Spectrum Disorders?
There is no single cause for ASD. Recent studies strongly suggest that some people have a genetic predisposition to autism, meaning that a susceptibility to develop the condition may be passed on from parents to children. Researchers are looking for clues about which genes contribute to this increased vulnerability, and many genes have been identified. However, abnormal genes are not the only cause.
In some children, environmental factors may also play a role. Studies of people with autism have found abnormalities in several regions of the brain, which suggest that autism results from a disruption of early brain development during fetal development. Some studies have shown abnormal brain shapes and structures in children with autism.
Other autism theories suggest:
- The body's immune system may inappropriately produce antibodies that attack the brains of children, causing autism. This theory has still not been scientifically proved.
- Abnormalities in brain structures cause autistic behavior.
- Children with autism have abnormal timing of the growth of their brains. Early in childhood, the brains of autistic children grow faster and larger than those of normal children. Later, when normal children's brains get bigger and better organized, the brains of kids with autism grow more slowly.
- Possible problems during pregnancy or delivery -- such as viral infections, metabolic imbalances, and exposure to environmental chemicals -- cause autistic behavior.
The Link Between Childhood Vaccines and Autism Spectrum Disorders
There has been ongoing controversy surrounding certain childhood vaccines and their relationship to ASD.
Many studies have looked at whether there is a link between autism and vaccines. To date, there is no known evidence that any vaccine can cause autism. A suspected link between the measles, mumps, rubella (MMR) vaccine and autism spectrum disorders has been suggested by some parents of children with autism. Typically, symptoms of autism are first noted by parents as their child begins to have difficulty with delays in speaking after age 1. Around this same time, the MMR vaccine is first given to children, but autism symptoms that arise around the same time are, scientists say, an unrelated chance occurrence. A study from Great Britain trying to prove this “link between autism and the MMR” was discovered to have been falsified by the lead author, who has subsequently lost his license to practice medicine.