New ADHD Diagnostic Tool Uses Genetic Variations
January 21, 2013

New Genetic Tool May Help Diagnose And Treat ADHD Kids

Brett Smith for - Your Universe Online

Despite being the most commonly diagnosed psychiatric condition among children, there is still no official tool for diagnosing Attention Deficit Hyperactivity Disorder (ADHD).

In her doctoral thesis, researcher Alaitz Molano, from Spain´s UPV/EHU-University of the Basque Country, attempted to fill this gap by not only identifying a way to improve the diagnosis of ADHD but also to enhance the current treatments.

Experts say between 8 and 12 percent of children are diagnosed with ADHD worldwide and 50 of these individuals continue to experience the symptoms of the condition into adult life. These symptoms include difficulty paying attention, being frequently distracted and having difficulty completing tasks. Some individuals with ADHD also display impulsive behavior and engage in excessive, inappropriate activities.

“All these symptoms seriously affect the social, academic and working life of the individuals, and impact greatly upon their families and milieu close to them,” Molano said.

To identify a genetic mechanism for ADHD, Molano studied the connection between certain DNA sequence among kids with ADHD and those without.

“We looked for all the associations that had been described previously in the literature worldwide, and did a clinical study to see whether these polymorphisms also occurred in the Spanish population; the reason is that genetic associations vary a lot between some populations and others,” Molano said.

Molano collected around 400 saliva samples from patients with ADHD along with 400 samples from healthy individuals without a history of psychiatric diseases. The analysis of over 250 DNA polymorphisms, or variations, led the scientist to uncover 32 polymorphisms associated with both the diagnosis of ADHD and the evolution of the disorder.

The analysis also confirmed the existence of the three subclasses of ADHD: lack of attention, hyperactivity, and a combination of the two.

“It can be seen that on the basis of genetics the children that belong to one subtype or another are different,” Molano said.

However, the genetic analysis was unable to establish a direct association between the polymorphisms and the patient´s response to pharmacological treatment. Molano said this might be due to the difficulty in collecting pharmacological data, adding that “in many cases the data on drugs we had available were not rigorous.”

She said her future studies will focus more on resolving the current lack of understanding regarding the genetic mechanisms behind ADHD drug interactions.

“We want to concentrate on the drug response aspect, obtain more, better characterized samples, and monitor the variables in the taking of drugs very closely, whether they were actually being taken or not, etc.,” she said.

Molano said she hopes this study will lead to better diagnostic tools and a better outcome for those diagnosed with the condition.

“The project was funded by Progenika Biopharma and the pharmaceutical company JUSTE SAFQ, but we also have another 10 collaborating clinics belonging to public and private centres in Spain, and it´s tricky getting them all to agree on matters like patents, marketing, etc. But our idea is that it should eventually be marketed and be welcomed,” she said.