ADHD and Autism may share a genetic link
By Liz Lockhart
Research which is currently emerging has discovered new genetic influences for Attention Deficit Hyperactivity Disorder (ADHD). It also finds that the genes appear to be associated with other neuropsychiatric conditions including Autism Spectrum Disorder ((ASD).
The study was conducted by researchers at the University of Toronto and is published in the advance online edition of Science Translational Medicine.
Researchers used gene-chip technology called microarrays to study the DNA of 248 unrelated patients with ADHD. They searched for copy number variants (CNVs) which are insertions or deletions affecting the genes. The CNVs may occur spontaneously or can be inherited.
Spontaneous CNVs were found in three of the 173 children for whom DNA of both parents were available. Inherited CNVs were found in 19 of 248 patients.
The researchers found that within the group of inherited CNVs, some of the genes that had previously been identified in other neuropsychiatric conditions including ASD. In order to explore this overlap, they tested a different group of CNVs and found that nine of the 349 children in the study carried CNVs that are related to ADHD and other disorders. All of these children had previously been diagnosed with ASD.
This finding suggests that some CNVs, which play a central role in ADHD, increase the risk for ADHD, ASD and other neuropsychiatric disorders.
People with ADHD usually also have at least one other condition such as mood, conduct or language disorders and anxiety. Up to 75% of people with ASD also have attention deficits or hyperactivity.
Senior author and neuroscientist Dr. Russell Schachar said ‘A lot of these associated problems probably arise from the fact that they are sharing genetic risk for different conditions.’
These findings could be reassuring for clinicians who see characteristics of different neuropsychiatric conditions in their patients. They can be concerned that they are over-interpreting these traits.
‘This research reinforces the notion that their gut observation is correct,’ Schachar said.
‘There are lots of different possibilities to explain why some common risks can manifest into different kinds of disorders,” he said, adding that while the new study observed this phenomenon, more research is needed to determine the cause.’ Schachar concluded.
Source: University of Toronto
