22 October 2024
Ground-breaking research led by QIMR Berghofer scientists has discovered hundreds of genetic variants involved in brain size which are also found in people with brain conditions including Parkinson's disease and Attention Deficit Hyperactivity Disorder (ADHD).
The study, published in the prestigious journal Nature Genetics , is the world's largest investigation into how genetic differences influence structures of the 'deep' brain, and provides an insight into the intricate relationship between our genetic makeup and brain health.
QIMR Berghofer researcher Associate Professor Miguel Rentería says the findings show that some of the same genetic variants that influence brain structure also influence the risk of brain-related conditions such ADHD and Parkinson's disease.
A/Prof Miguel Rentería from QIMR Berghofer
"There is strong evidence that ADHD and Parkinson's has a biological basis, and this research is a necessary step to understanding and eventually treating these conditions more effectively," he said.
To conduct the research, an international team of 189 researchers, led by Associate Professor Rentería and PhD candidate Luis García-Marín, analysed DNA data and brain MRI scans from 76,000 participants across 19 countries.
Associate Professor Rentería and his team observed 254 genetic variants which can influence the size of people's brain structure, and then studied whether some of these variants are also implicated in the risk of developmental, psychiatric, and neurological disorders.
"Genetic variants associated with larger brain volumes in key brain regions also increase the risk of Parkinson's disease, while variants linked to smaller brain volumes in key regions are associated with an increased risk of ADHD. It's worth noting that these are correlations, not causal relationships, and so interpretation must be approached with caution," he said.
"These findings suggest that genetic influences that underpin individual differences in brain structure may be fundamental to understanding the underlying causes of brain-related disorders."
Mr García-Marín said the research advances our understanding of the brain's development, variability, and evolution.
"It brings us closer to answering key questions about how genetics influence brain structure, and how we can potentially treat these conditions in future," he said.
The genetic effects on brain structure were consistent across people of European, African and Asian ancestry, highlighting the universal importance of genetic factors in brain development and function.
The study focused on subcortical brain structures including the hippocampus, amygdala, thalamus, caudate nucleus, nucleus accumbens, putamen, and globus pallidus. These subcortical structures are crucial for various brain functions, including memory formation, how we respond to reward and punishment, emotional regulation, motor control, and sensory processing.
The study used imaging and genetic data from international consortia, including the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis), an international effort based at the Keck School of Medicine of USC, which unites more than 1,000 research labs across 45 countries to hunt for genetic variations that affect the brain's structure and function, as well as CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology), UK Biobank, and the ABCD (Adolescent Brain Cognitive Development) study.
Professor Paul M. Thompson, the ENIGMA principal investigator and associate director of the USC Mark and Mary Stevens Neuroimaging and Informatics Institute at the Keck School of Medicine of USC says the findings are meaningful. "By conducting this research all over the world, we're beginning to home in on what has been called 'the genetic essence of humanity," he said.
