Twins and Autism Spectrum Disorders – here, we share some results of studies of twins and the incidence of autism.
While this information may seem scary at first, it is important to note two things: most of these studies relied on small samples groups, which may not provide the most reliable information. Also, the Columbia study limited itself to twins with siblings with autism, which has been identified as a risk factor for developing the disorder, and may have skewed the results.
For years, scientists, parents, and doctors have debated the causes of autism. At first, twin studies seemed to point to a genetic cause for the disease; however, the increased risk amongst fraternal twins (though not as high as that of identicals) seems to indicate that perhaps something about being a twin could also be a factor. This means that environmental factors in the womb, placental development, or even the experience of being raised with a same-age sibling could have some triggering effect for autism.
Some authorities estimate that the incidence of autistic disorders has increased over 172% since 1990. Others argue that the incidence of autism has remained static, but our ability to identify and assist autistic children has improved.
For more information on the studies cited in this article, and to access information on having twins assessed for autism, see the links below (Please copy and paste these into your browser):
Excess of Twins among Affected Sibling Pairs with Autism: Implications for the Etiology of Autism David A. Greenberg, Susan E. Hodge, Janice Sowinski, and Doug Nicoll from The American Journal of Human Genetics
Increased Rate of Twins among Affected Sibling Pairs with Autism
Catalina Betancur, Marion Leboyer, and Christopher Gillberg
from The American Journal of Human Genetics
AWARES article on Boston Autism Conference
Smile for the Cameraand for science (article about mom who kept twin diary) from the age.com.au
Warning Signs and Symptoms of Autism and Pervasive Developmental Disorder (PDD) from Autismwebhttp://www.autismweb.com/signs.htm
(Please copy and paste these links into your browser to view):