According to the Centre for Disease Control and Prevention, Autism Spectrum Disorder or ASD is a collection of conditions that can range in severity from the social awkwardness and narrow interests seen in Asperger’s to severe communication and intellectual disabilities.
Autism Spectrum Disorder now affects 1 in every 88 U.S. children, nearly double the rate in 2002. Genetic tests are beginning to provide some answers to long-standing questions about the causes of autism.
Testing will often reveal no abnormalities in the genes of a patient with autism. This at times leaves researchers without a clear explanation of the cause of the disorder. However, testing techniques are continuously improving and around 20% of autism cases are linked to known genetic abnormalities.
Finding the causes or risk factors in people’s genes can help predict whether siblings are likely to have the disorder and could lead to the development of new treatments. Finding causes through genetic analysis may also identify any existing risk of developing other health problems that accompany autism, such as cancer.
There is no test for Autism Spectrum Disorder, partly because environmental factors play such a major role in its development. People are diagnosed based on their symptoms and behavioral tests. After diagnosis researchers can look at the person’s genes in an effort to find genetic causes.
Both the American Academy of Paediatrics and the American College of Medical Genetics recommend that all children diagnosed with Autism Spectrum Disorder be tested for chromosome abnormalities. The newest tests, called chromosomal microanalysis, can identify submicroscopic deletions or duplications in DNA sequences known to be associated with autism.
Additionally, testing parents’ DNA of children who have autism can determine if the disorder was inherited. That can help to determine the risk of the parents having children in the future with autism. Testing may be recommended for patients who have not been diagnosed with autism but who are identified as being at high risk of developing it. Early diagnosis and treatment can help to improve a child’s IQ, language, and social skills.
However, the diagnosis should not be based on testing alone, environmental factors play an important role in the development of autism. Many cases of autism are the result of both genetic and environmental factors.
A study involving twins with Autism Spectrum Disorder, for example, determined that there is a seventy present chance that both twins will have the disorder, despite their identical genetic makeup. If the twins are fraternal the likelihood that both twins will have autism increases. This could be due to something in their shared prenatal environment.
Studies continue to grow. More and more families are participating, especially those with two or more affected children. More and more genes with links to autism are being identified. Progress is being made in understanding a disorder whose diagnosis and underlying causes have proven to be elusive in the past, with more research coming that will lead to an increased understanding of Autism Spectrum Disorder and to better treatment.