Autism rates in the United States are rising each year, making understanding its causes a high priority. The organization Autism Speaks reports that the disorder is more common among children than pediatric cancer, AIDS and juvenile diabetes combined. The culprits behind autism still are not fully understood, although the hormone testosterone might play a significant part in its development.
Understanding Autism
Autistic conditions fall under the category of pervasive developmental disorders. These disorders affect children in varying degrees, with some having few challenges handling daily life to others completely unable to care for themselves independently. Social and communicative difficulties are classic signs. Autistic kids might seem indifferent or, in contrast, might lack control of their emotions. Delays in speech might occur and some might never speak. Children with autism also tend to repeat certain behaviors and have trouble with changes in routine. The care, treatment and therapy that these children receive play a pivotal role in both their current development and adult lives.
Testosterone Link
The search for answers to why children develop autism has brought multiple theories to the forefront, with the role of testosterone being one of them. Autism affects three to four times more boys than girls, according to Autism Speaks. Research findings, published in the journal "Molecular Autism" in July 2010, suggest that exposure to higher levels of testosterone might help explain this statistic. The study's authors found that increased fetal testosterone exposure was associated with higher scores on the Quantitative Checklist for Autism in Toddlers among children ages 18 to 24 months. Male fetuses are exposed to surges of this androgen hormone during pregnancy, which might affect their brain development, according to a June 2011 article in "PLoS Biology."
RORA and Testosterone
Additional findings from George Washington University researchers offer more clues to the higher prevalence of autism in boys. Their study, published in February 2011 in "PLoS One," reveals that deficiency in the gene retinoic acid-related orphan receptor-alpha, or RORA, plays a role in excessive testosterone exposure during fetal development. In addition, RORA deficiency affects normal development of the brain's cerebellum, which is known to play a role in autism. In contrast, the hormone estrogen increases RORA levels, which could explain why autism prevalence in girls is so much lower.
Other Factors
Hormones are far from the only factors being studied in autism research. Maternal exposure to antigens, such as rubella, might be involved, and environmental chemicals also are being looked into, according to Autism Speaks. Central nervous system inflammation also might be a piece of the puzzle, encouraging research into the role of the immune system in autism. The National Institute of Neurological Disorders and Stroke reports that evidence suggests a genetic link: An identical twin's risk of having autism might be as high as 90 percent if his twin has the disorder. Children who have an autistic sibling have a one in 20 chance of being diagnosed as well.
References
- Autism Speaks: What is Autism?
- "Molecular Autism"; Foetal Testosterone and Autistic Traits in 18 to 24-Month Old Children; Bonnie Auyeung, et al.; July 2010
- "PLoS Biology"; Why Are Autism Spectrum Conditions More Prevalent in Males?; Simon Baron-Cohen, et al.; June 2011
- George Washington University; Autism's Testosterone Question; Danny Freedman; February 2011
- National Institute of Neurological Disorders and Stroke: Autism Fact Sheet
