A study from Geisinger has found that the Y chromosome may be associated with an increased risk for autism, providing a new way to understand why autism is more common in males. The findings were published today in Nature Communications.
Autism spectrum disorder (ASD) is a neurodevelopmental disorder noted for challenges in social interactions and communication, alongside repetitive behaviors and limited interests. Males are nearly four times more likely than females to be diagnosed with ASD, but the reason for this difference is not clearly understood.
One prevalent theory suggests that the variation in sex chromosomes between genders may be a contributing factor. Typically, females have two X chromosomes, while males have one X and one Y chromosome.
“A main theory suggests that the X chromosome has protective factors that help reduce the risk of autism in females,” explained Matthew Oetjens, Ph.D., a researcher at Geisinger’s Autism & Developmental Medicine Institute.
The research team, led by Dr. Oetjens and staff scientist Alexander Berry, Ph.D., aimed to explore how the X and Y chromosomes affect autism risk by studying ASD diagnoses in individuals with an unusual number of X or Y chromosomes, known as sex chromosome aneuploidy.
They reviewed the genetic and ASD diagnosis information of 177,416 patients participating in the Simons Foundation Powering Autism Research (SPARK) study and Geisinger’s MyCode Community Health Initiative. The results indicated that having an extra X chromosome did not affect the risk of ASD, but individuals with an extra Y chromosome were found to be twice as likely to receive an ASD diagnosis. This points to a potential risk factor linked to the Y chromosome, rather than a protective factor related to the X chromosome.
“Although these findings may appear to reflect the same idea, they motivate us to seek out autism risk factors on the Y chromosome instead of focusing solely on the protective traits of the X chromosome,” Dr. Berry noted. “However, more research is necessary to pinpoint the exact risk factor associated with the Y chromosome.”
This study further validates previous research which indicates that the absence of an X or Y chromosome, as seen in Turner syndrome, is linked with a significant increase in ASD risk. Additional studies are essential to uncover whether the autism risk factors tied to sex chromosome aneuploidy account for the gender differences in ASD prevalence.
