Schizophrenia genetic deletions linked to poorer cognition in study
University of Washington researchers found some gene deletions were tied to more severe cognitive problems in schizophrenia spectrum disorders.
By Tom Brennan · Health & Medicine Correspondent
3 min read
A University of Washington study links schizophrenia genetic deletions to lower cognitive performance in people with schizophrenia spectrum disorders, offering a possible explanation for why symptoms can vary so widely. The findings matter because weaker cognition in schizophrenia has been associated with forms of illness that are harder to treat, according to the university.
The study, published in the American Journal of Psychiatry, examined deletions in genes involved in regulating early brain and neuron development. University of Washington researchers reported that those deletions were associated with more severe features of schizophrenia spectrum disorders, especially poorer cognitive ability.
According to the University of Washington, schizophrenia affects about 23 million people worldwide and typically begins in late adolescence or in a person’s 20s. The condition can involve hallucinations, delusions, and disorganized thinking and behavior.
How do genetic deletions affect schizophrenia severity?
Genetic deletions are missing stretches of DNA. In this study, researchers focused on deletions affecting genes tied to early brain development and found that people with schizophrenia spectrum disorders who carried them tended to score lower on tests of memory, thinking and attention, according to the University of Washington.
Jennifer Forsyth, a co-author of the study and an assistant professor of psychology at the University of Washington, said the work points toward a subset of patients whose symptoms may be shaped by developmental genetic factors. The university said that understanding those factors could help identify people who might benefit from earlier or more targeted interventions.
What the researchers compared
The research team analyzed DNA from more than 600 people with schizophrenia spectrum disorders, according to the University of Washington. The researchers compared those data with genetic information from patients’ relatives, people without schizophrenia, and nearly 10,000 children in the Adolescent Brain Cognitive Development Study.
People with schizophrenia who had the deletions generally performed worse on cognitive tests than people with schizophrenia who did not carry the deletions, the university said. The researchers also saw similar but weaker patterns in the broader population, suggesting the variants may influence brain development beyond diagnosed schizophrenia.
The study does not show that the deletions determine a person’s outcome. Forsyth said, according to the university, that many genetic variants combine in complex ways and that the findings may help researchers understand how different risk profiles shape the way a disorder appears in an individual.
Brain structure findings differed from the usual pattern
The University of Washington said the same deletions were also tied to differences in brain structure, including higher gray matter volume and greater cortical thickness. Forsyth said that pattern runs counter to what researchers tend to see on average in schizophrenia, underscoring variation among patients.
The paper lists Forsyth among the authors, along with University of Washington psychology department researchers Jinhan Zhu, Zachary Trevorrow, Mahnoor Hyat, Ariana Chavannes, Sam Sievertsen and Sophie Ferreira-Ianone. Matthew Conomos, a senior research scientist in biostatistics at the university, was also a co-author.
Forsyth said the results could influence how researchers think about treatment directions, including approaches aimed earlier in brain development, according to the University of Washington. The study points to future questions about medication or gene-based strategies, but it does not report a new treatment.
This story draws on original reporting from Medical Xpress.