Common Genetic Basis Found in Eight Psychiatric Conditions

Recent research has revealed that eight different psychiatric disorders share an underlying genetic similarity.

A study released this year identified specific gene variants common among these conditions, examining their roles during brain development.

The US researchers discovered that many of these variants remain active for longer durations, potentially impacting various stages of development. This could open up avenues for treatments that address several disorders simultaneously.

“The proteins from these genes are also well-connected to others,” noted geneticist Hyejung Won from the University of North Carolina in January. “Modifications to these proteins could have widespread repercussions within the brain’s network.”

Back in 2019, an international group initially linked 109 genes to eight psychiatric disorders: autism, ADHD, schizophrenia, bipolar disorder, major depressive disorder, Tourette syndrome, obsessive-compulsive disorder, and anorexia. This might shed light on why these disorders frequently overlap, with estimates suggesting that up to 70% of those diagnosed with autism or ADHD also have the other condition—showing a troubling family clustering as well.

The team compared both unique and shared gene differences across these eight conditions. They analyzed nearly 18,000 variations in these genes by incorporating them into precursor cells that evolve into neurons, to see how they influence gene expression during human development.

This approach led to the identification of 683 genetic variants that affect gene regulation, which were further investigated in neurons from developing mice.

Genetic variants that influence multiple seemingly disconnected traits—known as pleiotropic variants—were found to facilitate many more protein interactions than those tied to specific disorders. Additionally, they were active in a wider range of brain cell types.

These pleiotropic variants also participate in regulatory processes that affect multiple developmental stages in the brain. This interconnectedness could explain why the same gene variants contribute to different psychiatric conditions.

“Historically, pleiotropy posed a challenge as it complicates how we classify psychiatric disorders,” remarked Won. “However, understanding its genetic foundations may help us develop treatments targeting these combined genetic factors, which could be effective for various disorders at once.”

This could prove to be an essential approach considering the World Health Organization’s estimate that one in eight people, totaling nearly one billion globally, are affected by some kind of psychiatric condition.

The findings were published in Cell.