Autism is a disease of children and to meet the strict definition of the disease must be diagnosed before the age of three. Although autism is a development disorder of the brain, it affects many aspects of health and behavior. Autistic children grow up to be autistic adults with certain behavioral challenges depending on the severity of their condition. About 1 in 150 US children are affected by a development disorder along the autism spectrum and are classified as having Autism Spectrum Disorder.
Individuals with autism have unusual behavior in three main areas:
- Limited social engagement skills with limited eye contact and inability to read others' body language
- Narrow interests and repetitive behaviors that can result in compulsions and rigid routines
- Communication difficulties such as delayed speech
There are several important questions about autism that are often the subject of media articles as well as scientific research.
How early can autism be detected?
Nine months, according to a recent report from McMaster's University. Researchers used eye tracker technology to measure eye direction while babies are looking at face, eyes and bouncing balls on a computer screen. Before this new technology, autism has usually been detected around the age of 2 or 3.
Is mild autism a variant of normal behavior?
Some people question whether mild autism is really a disease at all. Asperger's syndrome for example, is a mild developmental disorder that is on the autism spectrum but is very prevalent in certain professions such as computing. Silicon Valley has a very high percentage of individuals who fit the Asperger's profile, who lead successful and fulfilling lives working in the IT industry. Preference for working with limited social interaction in the quiet of the night hours is an advantage for many IT jobs. Could it be that Asperger's individuals are just normal folks that are a just a little more reclusive than most? Professor Simon Baron-Cohen, a British researcher, believes most men are autistic to one degree or another, evidenced by their preference for mechanistic thinking and limited communication skills. Autism can be considered and extreme form of "male-ness" according to this line of thinking.
Research tells us that the brains of those with Autism do function differently to those in non-autistic people and appear to be larger, at least in the early years. Brain abnormalities are found in three particular areas that correlate with the three major symptom types shown above in the description.
Can autism be inherited?
There is a genetic component to autism so the tendency to autism can be inherited. Scientists believe this based on research from Massachusetts General Hospital that found that a child's chances of developing autism jumped by a factor of 100 when a small chunk of chromosome 16 was missing or duplicated. However, this only explains autism in 1 out of every 100 children with the syndrome so there is obviously something else going on too. Other genes may be involved and the environment also has an effect. For example, older fathers have a 6 times higher chance of having an autistic child than younger fathers.
A large study of children with autism funded by the Center for Disease Control has begun in the US. Researchers will take regular biological samples and interview and test the children. The study will compare genetic and environmental differences between the children to help determine the role of genes and the environment in the development of the syndrome over five years.
Is autism considered an epidemic at the moment?
There are many stories in the news about autistic individuals and people with Asperger's syndrome at the moment. This does not necessarily mean there is an epidemic but it does seem as though the children are getting diagnosed more frequently than in the past. This is probably due to an increase in diagnosis of a problem that has been around for a very long time. Doctors now look harder and earlier for the symptoms with the hope that early diagnosis can lead to better chances to treat the development delays. It is not known whether the increase in autism is real, and due to particular interactions with genes and environment at them moment, or just due to better diagnosis.
A large study is underway in the UK to determine the number of children and adults with developmental problems that place them on the autism spectrum.
Do vaccines cause autism?
There is currently no evidence to suggest vaccines cause autism.
The theory about vaccines is based on the presence of a preservative in some vaccines called thimerosal. This additive contains mercury, which is known to be toxic even in small doses. Since 2001 vaccines in the US have not contained thimerosal (except for the flu vaccine) but autism rates have continues to climb. A 2008 study of 7-10 years olds in the New England Journal of Medicine has reported that children exposed to thimerosal through vaccines when the were young, did not appear to have any physical or mental difficulties. This study did not test for autism specifically. Some increased risk of tics in boys was found. A later interpretation of the study suggested the study was flawed in several ways so the data may not be as reassuring as initially thought. However, the benefits of vaccination still outweigh any potential risk based on this particular study.
The MMR (Measle, Mumps, Rubella) vaccine has also been thought to be associated with autism. Studies about 10 years ago seemed to suggest a link but more recent research has not found any evidence that MMR causes autism or development delays. Three studies to date have been conducted to specifically look at the link. The latest was conducted in the UK in 2008 and confirms data from the earlier two that there is no link between MMR vaccine and autism.
One highly publicized case was reported earlier this year where a little girl, Hannah Poling is considered to have developed autism after receiving a set of vaccinations for nine diseases at once in 2000, when thimerosal was still being used. Hannah was found to have an underlying disorder of the mitochondria in her cells (the mitochondria are the power houses of the cell) that may have put her at a higher risk of vaccine related problems including the onset of autism symptoms. It is unknown how the cellular disease, the vaccinations and the autism are all related but it is clear this was a very unusual case. A study presented at the American Academy of Neurolpgy in April this year showed that there is a subset of autistic children that do seem to have a mitochondrial defect that can cause muscle weakness. This weakness is believed to be genetic but further research is needed to confirm the genes involved.
The debate on vaccines and autism continues but for now, the benefits of vaccinations outweigh the potential, and as yet unproven, risks.
