Autism, or autism spectrum disorder (ASD), is a neurodevelopmental condition that can present in a range of ways, and can be diagnosed at any age. It can impact how a person may behanve, communicate, or learn. ASD also tends to be far more commonly diagnosed in males, although researchers are still determining whether that has to do with biases in the diagnosis of the condition, or if it simply affects males more often. One challenge is that scientists are still learning what causes autism, although genetics, environmental influences, and possibly other factors such as immunity, metabolism, or the microbiome may play a role.
Scientists have now found a link between ASD and a gene called DDX53. Variations in the gene were identified in ten ASD patients from eight families. The gene is related to the development and function of the brain, and it is located on the X chromosome. Most of the ASD patients in this study were male, so this gene could help explain some of the sex differences in ASD. The findings have been reported in the American Journal of Human Genetics (AJHG).
The investigators also searched through other databases containing genetic information from many ASD patients. This effort revealed 26 more ASD patients with rare DDX53 variants.
Additional research also reported in a separate AJHG study identified 59 other genetic variants in genes located on the X chromosome that are associated with ASD. Variations were found in a variety of genes such as DMD, FGF13, HDAC8, and one called PTCHD1-AS, which is located near DDX53.
In one case, a patient carried mutations in both DDX53 and PTCHD1-AS.
In unrelated work reported in npj Genomic Medicine, researchers analyzed genomic data from a cohort of ASD patients and their families. This study identified variants in 73 genes that have previously been linked to ASD, and which were carried by different ASD patients. The researchers also discovered variants that could increase the risk of ASD in 120 genes that have not been associated with ASD before this.
"Research suggests that there may be up to 1,000 genes associated with ASD susceptibility, and the genetic variants identified to date represent just a fraction of the disease burden," said senior study author Maria Chahrour, PhD, Associate Professor at UT Southwestern.
"We have a long way to go to fully understand the specific genetic causes of ASD, but studies like this one expand our knowledge, enable us to fine-tune future research, and could eventually lead to targeted therapies."
Sources: Scala et al American Journal of Human Genetics 2024, Mendes et al American Journal of Human Genetics 2024, UT Southwestern Medical Center, npj Genomic Medicine