Researchers have found a possible genetic link for attention deficit hyperactivity disorder (ADHD). But the researchers also stress that their evidence does not suggest a single gene or set of genes are responsible for ADHD.
Researchers led by Anita Thapar from Cardiff University in Wales analyzed DNA strands from 366 children who had been diagnosed with attention deficit disorder. They then compared DNA from 1,047 children without ADHD.
They found that the children in the ADHD group were over twice as likely to have large and rare variations in their DNA, called copy number variants — 15 percent compared to 7 percent in the control group.
However, the researchers could not explain why 85 percent of ADHD children examined did not have similar rare variations in their DNA, suggesting there is still a long way to go to unraveling the secrets of attention deficit disorder’s origins.
“We found that, compared with the control group, the children with ADHD have a much higher rate of chunks of DNA that are either duplicated or missing,” said Thapar.
“It’s going to be the start of a much more scientific venture because our findings are going to help unravel the biological basis of ADHD,” continued Thapar. “Of course, this won’t happen immediately.”
“The first gains beyond today’s study might be initial insights into the pathogenesis and neurobiology of brain development as influenced by these genetic variants,” said J. Peter Burbach, PhD, of University Medical Center Utrecht in an accompanying editorial.
“This knowledge will eventually enter the clinic and might affect the way people think about and treat neurodevelopmental disorders by accounting for the biological consequence of the specific patient’s genotype.”
This is apparently the first research data to connect attention deficit disorder to genes, suggesting that it is not purely a behavioral or psychological disorder, or one caused by badparenting.
Instead, the study suggests the complicated etiology of ADHD — similar to other serious mental disorders like depression and bipolardisorder.
The study also found a significant genetic overlap between ADHD and autism, two disorders that previously had been thought to be completely separate and distinct entities. This additional finding suggests there may be a shared biological basis to these two mental disorders.
The study was published online in The Lancet.