Understanding genetics can be complicated, often involving a complex web of interactions rather than straightforward answers. However, a recent study has possibly identified a notable exception.
Researchers have linked changes in a single gene, known as GRIN2A, to psychiatric conditions, including early-onset schizophrenia.
“Our findings suggest that GRIN2A may be the first gene identified that can independently cause a mental illness,” says Johannes Lemke, a geneticist from Leipzig University in Germany, who co-led the study.
Mental health issues, like severe depression or schizophrenia, are generally believed to arise from countless genetic interactions. Yet, this assumption might not always hold up.
Recent evidence strongly indicates that variations in the GRIN2A gene are linked to instances of schizophrenia appearing in childhood or early adolescence—much earlier than is typically the case.
By examining a registry of the largest known group of GRIN2A patients, the researchers conducted an international study on how mutations in this gene affect mental health.
Out of 121 individuals with potentially harmful mutations in the GRIN2A gene, the team identified 25 who had diagnosed mental disorders, including various mood, anxiety, psychotic, personality, and eating disorders.
Notably, nearly all these individuals had the “null” variant of GRIN2A, indicating that it was not functioning.
“We demonstrated that certain variants of this gene are associated not just with schizophrenia but also with other mental health issues,” Lemke explains.
“What’s particularly interesting is that these disorders often manifest in childhood or adolescence when there’s an alteration in GRIN2A, unlike the typical adult onset.”
Moreover, while mutations in the GRIN2A gene are usually affiliated with neurodevelopmental issues like epilepsy or intellectual disabilities, some study participants exhibited only psychiatric symptoms.
This raises the possibility that alterations in GRIN2A can lead to isolated mental health conditions without other neurodevelopmental complications.
“Incorporating genetic testing into the diagnostic process for affected individuals could enhance diagnosis and potentially lead to personalized treatment options,” the authors suggest.
GRIN2A plays a role in forming part of a glutamate receptor in the brain, which is essential for excitatory brain activity. The dysfunction of these receptors is closely linked with conditions like epilepsy and schizophrenia.
Four participants in this study had previously been treated with L-serine, an amino acid that stimulates glutamate receptors and helps reduce seizures. Interestingly, all four reported improvements in their mental health conditions following treatment.
One individual no longer experienced hallucinations; another showed progress with their behavioral issues. The other two saw reductions in paranoid symptoms and fewer seizures.
The small size of the study may pose limitations, but it implies that not all psychiatric disorders stem from a mix of genetic variants. In fact, some conditions might be accurately treated based on their specific genetic makeup.
Of course, the precise role of the GRIN2A gene in these disorders remains an area for further research.
This study was published in Molecular Psychiatry.
