Large brain volume study finds genetic links to Parkinson’s disease and ADHD

In one of the largest studies of DNA and brain volume, researchers identified 254 genes that make up important parts of the “deep brain,” including those that control memory, motor skills, addictive behavior and more. The findings were published in the journal Nature Genetics.

The study is supported by the Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) consortium, an international effort based at USC’s Keck School of Medicine, which brings together more than 1,000 research labs in 45 countries to hunt for genetic variants. which affects the structure and function of the brain.

“Many brain diseases are known to be partly genetic, but from a scientific point of view, we want to find the exact genetic changes that cause these,” said Paul M. Thompson, Ph.D. ., organization manager. of USC’s Mark and Mary Stevens Neuroimaging and Informatics Institute and principal investigator of ENIGMA.

He said: “By doing this research around the world, we are beginning to understand what has been called ‘human genetics.’

Identifying which brain regions are larger or smaller in some groups (for example, people with certain brain diseases) compared to others can help scientists begin to understand what causes work on the brain. Finding the genes that control the development of those brain areas provides more information about how to intervene.

In the study, a group of 189 researchers from around the world collected DNA samples and brain magnetic resonance images, which measured the volume in important subcortical areas – also known as the “deep brain” -from 74,898 participants.

They then conducted genome-wide association studies, or GWAS, a method that can identify different genetic variants associated with different traits or diseases, to find other brain-genetic relationships that were have a higher risk of Parkinson’s disease and attention deficit/hyperactivity disorder (ADHD). ).

“There is strong evidence that ADHD and Parkinson’s have a biological basis, and this research is a necessary step towards understanding and treating these conditions more effectively,” said Miguel Rentería, Ph.D., assistant of computational neurogenomics Queensland professor. Institute of Medical Research (QIMR Berghofer) Australia and principal investigator of Nature Genetics study.

“Our findings suggest that the genetic influences that underlie individual differences in brain structure may be important in understanding the underlying causes of brain-related disorders,” he said.

Deep brain learning

The researchers examined brain volume in key subcortical areas, including the brain stem, hippocampus, amygdala, thalamus, nucleus accumbens, putamen, caudate nucleus, globus pallidus and ventral diencephalon. These areas are important for forming thoughts, controlling emotions, controlling movement, processing sensory input from the outside world, and responding to reward and punishment.

GWAS revealed 254 genes associated with brain volume across those regions, explaining up to 10% of the observed variation in brain volume in study participants. Although previous studies have clearly linked certain areas to diseases, such as the basal ganglia and Parkinson’s disease, a new study reveals which genes shape the brain’s height with greater precision.

“This paper, for the first time, pinpoints exactly where these genes are active in the brain,” providing the beginning of a road map for intervention, said Thompson, who is also a professor of ophthalmology, pediatrics , neuroscience, psychology and behavioral sciences. , radiology, biomedical engineering and electrical engineering at the Keck School of Medicine.

Researchers note that the study is related, so more research is needed before genes can be linked to various diseases.

From Rentería’s group, doctoral candidate Luis García-Marín and postdoctoral researcher Adrian Campos, Ph.D., were first authors of the study.

In addition to data from ENIGMA, researchers also used data from Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE), the UK Biobank and the Adolescent Brain Cognitive Development (ABCD) study. Summary statistics are available for researchers to download from the ENIGMA consortium.