Nine specific genes on the X chromosome have been identified as the reason why autism is four times more common in boys than in girls.
The gender gap in autism has been one of the biggest mysteries in psychiatry for decades. By modeling rare genetic variations, researchers pinpointed a group of genes on the X chromosome that contribute to this prevalence ratio. Because males have only one X chromosome, a single variation in these genes can have a much larger impact than it would in females, who have a second copy to buffer the effect. This study provides the first concrete genetic explanation for why the female protective effect exists. Understanding these specific pathways could lead to more accurate early screening and personalized support for children with ASD.
Modeling rare coding variation on chromosome X provides insight into the genetics and differential sex prevalence of autism spectrum disorder
medRxiv · 10.64898/2026.05.04.26352380
Autism spectrum disorder (ASD) is estimated to be up to four times as common in males as in females, yet the causes of this prevalence difference are not well established. One possible driver is genetic variation on the X chromosome, as it contains genes capable of contributing to ASD (e.g., PTCHD1, MECP2) and is known to play a role in genetic disorders with differential sex prevalence (e.g., color blindness). However, a lack of power compared to the autosomes combined with the complexities of