Researchers Unlock Pattern of Gene Activity for ADHD
NIH researchers have successfully identified differences in gene activity in the brains of people with attention deficit hyperactivity disorder (ADHD).
The study, led by scientists at NHGRI, found that individuals diagnosed with ADHD had differences in genes that code for known chemicals that brain cells use to communicate. Results published in Molecular Psychiatry, show how genomic differences might contribute to symptoms.
Postmortem studies are rare, due to limited donation of brain tissue, but they are invaluable in providing researchers direct experimental access to the brain. To date, this is the first study to use postmortem human brain tissue to investigate ADHD.
The researchers used a genomic technique called RNA sequencing to probe how specific genes are turned on or off, also known as gene expression. They studied two connected brain regions associated with ADHD: the caudate and the frontal cortex, regions known to be critical in controlling a person’s attention.
“Multiple types of genomic studies are pointing towards the expression of the same genes,” said Dr. Gustavo Sudre, associate investigator in HGRI’s Social and Behavioral Research Branch, who led this study. “Interestingly, these gene-expression differences were similar to those seen in other conditions, which may reflect differences in how the brain functions, such as in autism.”
Researchers found that these differences affected the expression of genes that code for neurotransmitters, chemicals that brain cells use to communicate with one another. In particular, the results revealed differences in gene expression for glutamate neurotransmitters, which are important for brain functions such as attention and learning.
ADHD affects about 1 in 10 children in the U.S. and symptoms may persist into adulthood. Individuals with ADHD may have difficulty concentrating, which can affect their ability to complete daily tasks and focus on school or work.
Researchers had previously been able to identify genes associated with ADHD but had been unable to determine how genomic differences in these genes act in the brain to contribute to symptoms, until now.