“These findings provide the first biomarker-based evidence that a class of known maternal autoimmune disorders is related to autism in offspring.”
That was the conclusion reached in the study by Alan Brown and colleagues* drawing on a research collaboration between the United States and Finland.
Based on data collected from the Finnish Prenatal Study of Autism (FiPS-A), looking at possible pregnancy and birth factors associated with an offspring diagnosis of autism, researchers set about analysing archived serum samples from mums-to-be for positivity to thyroid peroxidase antibody (TPO-Ab), an immune reaction to an important enzyme involved in the production of thyroid hormones. The presence of TPO antibody is more usually associated with a diagnosis of Hashimoto’s thyroiditis, an autoimmune condition.
Researchers found that in pregnancies that eventually gave rise to a child with autism, a positive result for TPO antibody was more likely to be present compared with controls with offspring who were not subsequently diagnosed with autism. Although not universally linked, the authors concluded that a positive TPO antibody result in maternal serum elevated the odds of offspring autism by approximately 80% compared to those negative for the antibody.
Whereas previous research had hinted at a possible relationship between thyroid hormones and diagnoses like autism or ADHD (attention-deficit hyperactivity disorder), Brown and colleagues did not find any significant difference in maternal thyroid hormone concentrations in those mothers with a child with autism compared to controls.
Various other autism research studies have suggested that a familial history of several autoimmune conditions may translate into an increased risk of offspring autism. Autoimmune conditions such as coeliac (celiac) disease, type 1 diabetes and inflammatory bowel disease have been tentatively put forward as conveying some increased risk, albeit not conclusively. Alongside the presence of other autoantibodies – that is, antibodies reacting against ‘self’ tissues – in some mothers of children with autism, there are increasing moves to recognising some role for autoimmunity for at least some people on the autism spectrum.
* Brown AS. et al. Maternal thyroid autoantibody and elevated risk of autism in a national birth cohort. Prog Neuropsychopharmacol Biol Psychiatry. 2015 Mar 3;57:86-92.
Read more about this study at: http://questioning-answers.blogspot.com/2015/01/maternal-thyroid-autoantibody-and-offspring-autism-risk.html