Is there a connection between autoimmune diseases and autism? While there is no known cause of autism, experts have theories about a number of possible triggers ranging from environmental to genetic factors. Autoimmune diseases are among the many possible causes. A recent National Institute of Mental Health study argues that there is a link between certain autoimmune diseases and autism.
Autoimmune Diseases and Autism
Autism is a pervasive developmental disorder that produces impairments in language, social interaction and communication skills. Impairments can be mild or severe. Children are usually diagnosed in early childhood by the age of two years old. The cause of autism is unknown but there are many theories, including a genetic tie. Experts have examined whether or not autoimmune diseases could be a possible autism source. The theory about autoimmune disease supports the argument for a possible genetic trigger for pervasive developmental disorders.
Autoimmune diseases are medical conditions in which the immune system attacks body tissue. Examples of autoimmune diseases are diabetes, multiple sclerosis, Crohn's disease and celiac disease. Some of these conditions, such as type 1 diabetes mellitus, have been shown to have link with other neurological conditions. Mothers with autoimmune diseases are at higher risk for premature births and some experts believe that the incidence of autism in premature babies may be connected.
2009 National Institute of Mental Health Study
A 2009 study by the US National Institute of Mental Health and the Aarhus University Research Foundation in Denmark found that there is a possible link between autism and certain autoimmune diseases. Among the autoimmune diseases that appeared to have a connection to autism were type 1 diabetes mellitus, celiac disease and rheumatoid arthritis.
The study evaluated the medical information from the Danish national health care registries on all Danish children born in Denmark between 1993 and 2004 and compared it to the medical records of their parents and siblings. The researchers were looking for any incidences of an autoimmune disease diagnosed prior to an autism diagnosis in the children or their family.
The research team found that 3,325 children out of 689,196 had autism. Mothers with rheumatoid arthritis had a 70 percent risk of having children with autism. Women with celiac disease were nearly three times more likely to have children with autism than women without the condition. Children born to families with parents and siblings with type 1 diabetes mellitus had an increased risk for autism.
It is unknown exactly why the presence of these autoimmune diseases increased a risk for autism. Researchers point to possible factors such as a genetics, an abnormal uterine environment during fetal development due to the autoimmune disease, birth weight or premature delivery.
This was the first study to find a connection between autoimmune diseases and autism. Researchers argue that the findings support the genetic basis for autism and that the study can help future research figure out which areas of the genome are connected to autism.
The study was published in the August 2009 edition of the Pediatrics journal.
Studies Against Autoimmune Connections to Autism
Earlier studies examined whether or not autoimmune diseases were connected to autism and did not find any evidence of a connection. Two of the important studies involved the autoimmune disease celiac disease.
1997 University of Catania study
Researchers at the Pediatric Clinic of the University of Catania in Italy studied 120 patients with celiac disease with 11 patients with autism and 11 patients in a control group in a controlled study. None of the patients with autism had any traces of celiac disease and none of the patients with celiac disease tested positive for autism.
2007 American Academy of Neurology Study
In 2007, the American Academy of Neurology conducted a study of a possible link between autism and autoimmune diseases with a research team at Tehran University in Iran. The research team compared the blood samples of 34 autistic children with 34 neurotypical (average development) children. All of the children with autism tested negative for celiac disease.
The researchers found that celiac disease did not increase a risk for autism. However, they also recommended more research for possible connections between autism and autoimmune diseases like celiac disease.
There is no conclusive evidence of a link between autoimmune disease and autism. Recent studies show conflicting results. However, the 2009 National Institute of Mental Health study presents compelling evidence that more research is necessary to investigate any possible connection between autism and autoimmune disease.