A 2009 study published in Pediatrics used the nationwide psychiatric health registry in Denmark to re-examine the potential link between autoimmune diseases, particularly in the mother, and Autism Spectrum Disorder (ASD). Using a sample size over ten times larger than previously studied, their findings confirmed an association between autoimmune disease and ASD.

Multiple research approaches have been used throughout the years to uncover a potential relationship between immune function and autism, and while producing very intriguing data, the size of these studies has been limited and the findings have not always been replicated. This study utilized the nationwide health care system in Denmark to focus on the relationship between familial autoimmune diseases and ASD, including virtually all of the children born in the country between 1993 and 2004 (over 680,000 children).

After locating those with diagnoses of an ASD, the authors used other databases to track down information on the presence or absence of twenty-six different autoimmune disorders in the parents or unaffected siblings. Their results confirmed previously reported links between familial type 1 diabetes and ASD, as well as between rheumatoid arthritis and ASD, discovering for the first time that rheumatoid arthritis in the mother, but not the father, is associated with increased risk for ASD. The authors also uncovered the first association between ASD and untreated celiac disease in mothers.

By using one of the largest and most comprehensive national health databases, this study provides additional clues regarding the association between immune system dysregulation and ASD. The associations found with specific autoimmune diseases and whether the disease is present in mothers versus fathers provide important clues about the biological mechanisms that may lead to autism. For instance, because the risk of ASD was increased only when the mothers, but not the fathers, had rheumatoid arthritis, the authors hypothesize that the link to autism may be due to exposure to maternal antibodies secreted during pregnancy, or other alterations within the prenatal environment.

A relatively new focus in the search for the causes of ASD is the complex interaction between the immune function of a mother during pregnancy and the biological impact this may have on the early brain development of her child. In contrast, the association between type 1 diabetes and ASD was found if either parent was diabetic indicating that this link may be explained by a genetic factor that is related to both diabetes and autism. "This study suggests that looking at the associations with familial autoimmunity may be used to narrow down the search for autism risk factors, both genetic and environmental," said Dr. Colamarino.

"Not only does this research provide insights into causes and treatments, it provides a scientific context to prioritize funding for further research" remarked Dr. Dawson. "Autism research is a slow and incremental process. We see that epidemiological, genetic and environmental discoveries proceed simultaneously, with findings in one, advancing the other. To proceed in all areas of autism research concurrently requires a tremendous level of funding support." Autism Speaks has committed more than $141 million to date to fund research into the causes, diagnosis and treatment for autism through 2014. It is currently funding research into potential genetic and environmental risk factors involved with autism, identification of the biological pathways that underlie autism, as well as improved methods of early diagnosis and new treatment models." Read more about Autism Speaks' science portfolio here and the annual letter from the Chief Science Officer here.

Further Dr. Dawson explained that money spent on research is well spent. According to a 2007 Harvard School of Public Health study, it costs approximately $35 billion each year to care for people with autism - a number that has clearly increased over the past two years with the rising prevalence among the youngest people with ASD and a growing demand for housing, work skills and opportunities, healthcare, and other services that simply do not exist for adults with ASD. In FY 2008, total federal spending on autism research was just $177 million, expected to increase to $282 million in FY 2009 due to a one-time infusion of $89 million in stimulus spending.

During his campaign, President Obama committed to $1 billion of annual federal spending on autism by 2012. In October 2009, the President identified autism as one of his administration's top three public health priorities. Increased funding for autism research that defines causes and leads to effective treatments will clearly offset the growing cost to the public associated with caring and services for the still increasing number of individuals with autism.