Although there continues to be countless questions related to the cause of autism spectrum disorders (ASD), it is undisputed that rates of ASD are higher in males than females. In fact, males are nearly five times more likely to be diagnosed with ASD than females.
Some scientists believe that characteristics of the brain that vary between the sexes may explain the differential appearance of ASD. One primary difference between male and female brains is the thickness of the cortex — the outer layer of the cerebrum that plays a vital role in consciousness. Male brains tend to have a thinner cortex compared to female brains, leading Christine Ecker, a neuroscience professor at Goethe University in Frankfurt, Germany, to begin a new study that examined cortical thickness to determine whether brain anatomy differences were connected to a higher probability of autism in males.
The study, published in JAMA Psychiatry, consisted of Ecker and her co-authors examining brain MRIs of 98 adults with ASD (49 male, 49 female) and 98 adults without the disorder (51 male, 47 female), and comparing the cortical thickness. The research found that the thinner the cortex, regardless of gender, the more likely the person was to have ASD. In women, those with thinner, more “male-like” cortical thickness readings were about three times more likely to have ASD than women with thickness readings expected of unaffected women (Park, 2017).
Ecker’s primary takeaway from the study is the prospect that a thicker cortex in women might provide a defense against developing autism. Understanding the role that cortex thickness plays in developing autism could guide researchers towards more anatomy-specific factors that cause autism, and potentially offer clues about how to treat its symptoms.
In the conclusion of the study, the authors stress that “In addition to genetic and environmental factors, normative sex-related phenotypic diversity should thus be taken into account when determining an individual’s probability of ASD” (Ecker et al., 2017). It remains unclear whether a thinner cortex is a direct cause of autism, or simply a symptom of the disorder and thus the normal variations in thickness between male and female brains should be considered.
Looking forward, Ecker hopes to expand on her research to include investigating the potential functional changes the varying thicknesses have on male and female brains to determine if they can be connected to ASD. Ecker also hopes to track the variations in cortex measurements over the lifespans, to see if the male and female differences remain from infancy throughout adolescence or whether they arise later in life.
The release of the study highlights the need for continued research in an effort to determine the cause of ASD. With 1 in 68 children diagnosed today, autism is one of the fastest-growing developmental disorders in the United States with 1 in 42 boys being diagnosed with ASD, a statistic that is the central basis of this new study. Determining why more males are affected by autism than females is an important aspect of autism diagnosis, which may lead to groundbreaking findings on the main cause of the disorder.
Ecker, C., Andrews, D. S., & Gudbrandsen, C. M. (2017). Association Between the Probability of Autism Spectrum Disorder and Normative Sex-Related Phenotypic Diversity in Brain Structure. JAMA Psychiatry. Retrieved February 12, 2017, from https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2601066?utm_source%20=Silverchair_Information_Systems&utm_campaign=FTM_02062017&utm_conte%20nt=news_releases&cmp=1&utm_medium=email
Park, A. (2017, February 8). Why Autism Affects Boys More than Girls. Retrieved February 12, 2017, from http://time.com/4663196/autism-spectrum-disorder-gender/