Celiac.com 07/08/2009 - Kids whose moms have autoimmune diseases such as type 1 diabetes, rheumatoid arthritis and celiac disease face a risk of autism that is up to three times higher than that of the general population, according to a new study.
Although earlier studies have documented a connection between autism and a maternal history of type 1 diabetes and rheumatoid arthritis, this is the first study to document a link between autism and celiac disease, according to the study's authors.
Eaton's team collected data on 3,325 Danish children diagnosed with autism spectrum disorder, including 1,089 diagnosed with infantile autism. All of the children were born between 1993 and 2004, and their data was part of the Danish National Psychiatric Registry. Data on family members with autoimmune diseases came from the Danish National Hospital Register.
The data showed that children whose mothers had autoimmune disease faced a higher risk of developing autism spectrum disorder than children of mothers who did not have these conditions. Moreover, children with a family history of type 1 diabetes faced an increased risk of infantile autism.
Overall, the increased risk of autism in people with autoimmune diseases is not huge, Eaton said. "The increased risk for type 1 diabetes is a little less than two times, for rheumatoid arthritis it's about 1.5 times and for celiac disease it's more than three times," Eaton said. "That's enough to impress an epidemiologist, but not enough to make anybody in the general population start changing their behavior."
Eaton added that this finding "reinforces the suggestion that autoimmune processes are connected somehow with the cause of autism and autism spectrum disorder, and...may point a flashlight to areas of the genome that connect to autism."
The finding itself has no clinical significance, says Eaton, but could guide future efforts by researchers to determine the cause or causes of autism.
One reason autoimmune diseases might have a role in autism lies in genetic history, Eaton said. Children who were underweight or premature at birth face a higher risk for autism, and both of these obstetric problems are associated with celiac disease, he added.
There may be a significant overlap "in the genetics of some of the autoimmune diseases and autism," he said. "Autism is strongly inherited, but we don't have the faintest idea where...this finding is on the pathway of finding the cause of autism." Various environmental triggers may also affect the fetus, he said.
Lead researcher, Dr. Hjordis O. Atladottir, from the Institute of Public Health at the University of Aarhus in Denmark calls the findings important because they support the theory that autism is somehow tied to problems with the immune system.