Study By Aarhus University, Denmark Shows That The Same Genes Are Linked To Autism and ADHD
Globally, approximately 1.6 percent of schoolchildren have autism and 2.8 percent are diagnosed with ADHD. Autism and ADHD are different developmental disorders, but they can have certain common symptoms. For example, children with autism can demonstrate violent or aggressive behavior, be impulsive, and have problems in school and with social relations and these same symptoms can be shared by children with ADHD.
Medical researchers from iPSYCH, Denmark's largest research project in the field of psychiatry, have now discovered that the similarities between the two diagnoses can be linked to changes in the same genes
. The new study is the largest study to date of rare mutations in the genome of people with ADHD
Dr Anders Børglum, who is professor at Aarhus University, principal investigator at iPSYCH and one of the leading researchers behind the study told Thailand Medical
News, "The very fact that mutations are found to the same extent and in the same genes
in children with autism
and in children with ADHD
, points towards the same biological mechanisms being involved,"
Dr Børglum added, "This is the first time that the genome has been mapped so comprehensively for both ADHD
, and the discovery that children with ADHD
have the same amount of deleterious gene
mutations in their DNA as children with autism
is both striking and quite surprising."
The results of the study point directly towards which biological causal mechanisms are shared by ADHD
Dr Børglum explained, "In the study, the gene that is most frequently affected by mutations in people with ADHD
is the so-called MAP1A gene
. The gene is involved in the formation of the physical structure of nerve cells ,their inner 'skeleton', so to speak and is important for the development of the brain."
This represents a breakthrough as this is the first time that this gene has been linked to the development of ADHD
, and the mutations found by the researchers give a significantly increased risk of developing autism
Dr Børglum further explained, "We discovered an increased burden of mutations that destroy or severely affect the MAP1A gene
in those with ADHD
, while very few of the control subjects had such changes in t
This implies that the risk of ADHD
increases by more than 15 times for people who carry such a mutation. The researchers have analyzed the genes
of approximately 8,000 people with autism
, and 5,000 people without either of the two disorders, all from Denmark. The study also incorporated additional data from approx. 45,000 international control subjects who did not have any psychiatric disorders.
The researcher explained, "The study shows that many more genes
can be identified directly by studying more people in a similar way with extensive DNA sequencing, thereby providing a more complete picture of the biological causal mechanisms and possible approaches to medical treatment."
As part of the project, Børglum and his colleagues have had access to samples from the Danish National Biobank at the Statens Serum Institut and to data from the Danish Psychiatric Central Research Register. People born in Denmark between 1981 and 2005 were matched with diagnoses of autism
and mental retardation.
The study was carried out in collaboration with the Broad Institute and Harvard.
Reference: Satterstrom et al. (2019) Autism spectrum disorder and attention deficit hyperactivity disorder have a similar burden of rare protein-truncating variants. Nature Neuroscience. DOI: https://doi.org/10.1038/s41593-019-0527-8