A new study published in the Molecular Psychiatry scientific journal has revealed that 75 percent of the genes associated with autism spectrum disorder (ASD) are also linked to schizophrenia.

The paper notes that ASD is “one of the highly heritable neuropsychiatric disorders” and schizophrenia also “has high heritability estimates.”

Though ASD is apparent in early childhood while the onset of schizophrenia happens in adulthood, clinical reports indicate that the two conditions co-occur at rates higher than in the general population. In addition, there is some overlap of symptoms in the realm of impaired social interaction.

Previous studies that examined the genetic connection between the two disorders have identified only a few shared genes.

“The new findings reveal a much larger quantity of shared genes, and this is a very significant breakthrough in research,” said Prof. Shani Stern from the Sagol Department of Neurobiology at the University of Haifa, who led the study.

The researchers’ analysis provides additional support to the assertion that people with ASD may have an increased risk of schizophrenia.

Stern’s students, in cooperation with Prof. Ahmad Abu-Akel from the university’s School of Psychological Science, conducted a quantitative meta-analysis that examined a series of genetic research studies over the past decade.

The goal was to identify genes associated with ASD, which is considered a complex task due to the wide range of symptoms and the large number of genes involved.

The researchers also utilized meta-analysis to identify the shared phenotypes (observable traits, such as height, eye color and blood type) found in the nerve cells of people with ASD.

After analyzing the findings, the researchers discovered that 75% of the genetic variants that were attributed to ASD are also associated with the genes expressed in schizophrenia. Further analysis of the strongly associated common genes revealed that 45% of the variants are shared between both disorders.

One of the most significant genes shared by the two disorders is CACNA1C, which is responsible for providing instructions for making one of several calcium channels. It is often associated with bipolar disorder and schizophrenia.

The other two major genes in common are TCF4, which provides instructions for the protein involved in developmental processes, and SORCS3, which codes for the protein that suppresses cytokine signaling.

“This significant genetic overlap between [the two disorders], coupled with the convergence towards similar synaptic deficits, highlights the intricate interplay of genetic and developmental factors in shaping the shared underlying mechanisms of these complex neurodevelopmental and neuropsychiatric disorders,” the authors wrote.

“Identifying common pathways can offer valuable insights that could potentially inform more effective and targeted interventions for both disorders.”