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Julia K. Pinsonneault, PhD

Award Name Pilot Award

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Markers of Drug Response in Autism

Julia K. Pinsonneault, PhD, has been awarded a supplemental pilot award for her research study, “Genetic Contributions to ADHD Subtypes and Markers of Drug Response in Autism,” through the expansion of the Pilot and Collaborative Translation and Clinical Science program. The expansion was made possible by funds from the American Recovery and Reinvestment Act (ARRA).

Pinsonneault began writing her own grants and applied for the CCTS pilot award a year ago when she was promoted to research scientist.

Pinsonneault’s interest in studying the pharmacogenetics of ADHD and autism arose during her studies of the molecular genetics of the dopamine transporter. She read in several publications that the dopamine transporter is a candidate gene for ADHD and wanted to test what she learned about the gene in a clinical population.

Pinsonneault was introduced to Mike Aman at the OSU Nisonger Center, an interdisciplinary program with a focus on developmental disabilities. She said although Aman “wasn’t working so much with ADHD anymore,” he was interested in studying a population of autistic children with ADHD symptoms. The two decided to collaborate, which was how Pinsonneault came to be the principal investigator of her study.

According to the CDC, it is estimated that three to seven percent of school-aged children have ADHD. Autism is a much rarer disorder, affecting one in 110 children in the United States. However, according to Pinsonneault, about 60% of autistic children also exhibit ADHD or hyperactivity symptoms. But because these children were already diagnosed with autism, the DSM-IV didn’t allow for the diagnosis of both.

Pinsonneault believes the same candidate genes that may be contributing to ADHD in typically-developing children might also be functional in autistic children with ADHD symptoms.

Individually, certain polymorphisms may not cause anything but a slight variation in the level of a protein, such as a receptor for a neurotransmitter. However, the combination of certain polymorphisms may produce an additive effect that could potentially lead to a full-blown, complex disorder.

“We’ve been scanning genes for functional polymorphisms that affect RNA levels using a technique called allelic expression imbalance, which is a way of measuring the quantity of one allele relative to the other allele,” Pinsonneault said.

All humans have two alleles: one inherited from their mother and one from their father. Despite having two copies of the same gene, there may be slight variations between the alleles.

Studying if one allele could be expressed higher or lower than the other allows Pinsonneault and her team to use genetics and statistical research to scan the identified gene for other polymorphisms that may be the cause of the difference in expression imbalance.

Pinsonneault and her team are using the saliva of autism subjects to collect DNA data for analysis. The subjects spit into a collection chamber, which contains a buffer that preserves the saliva. The kits omit the need for a nurse and can be transported at room temperature, making the collection of saliva samples easier than blood samples.

The short term goal of the study is to increase recruitment and obtain more subjects. Long term, Pinsonneault hopes her hypothesis about the dopamine transporter is correct; that there’s really an effect of the functional polymorphisms she’s been studying.

The dopamine transporter is a drug target for stimulant medications used to treat ADHD symptoms.

Pinsonneault described today’s approach to prescribing medications to be “one size fits all.” In reality, for some individuals—due to their genetic make-up—certain medications may enter the body too quickly or too late to warrant effective results.

“There’s probably genetic reasons why certain medications work in some people and don’t work in others,” Pinsonneault said. “There are very few polymorphisms right now that are tested before patients are allowed to be given certain medications, so we’re hoping that we can identify more such things that would be valuable.

She and her team hope their study leads to genetic testing for polymorphisms so that opportunities to treat a patient are not wasted.

“What you see in the movies is way in the future,” Pinsonneault said. “You can’t just look at somebody’s DNA and say ‘they’re going to die at age 60 from heart disease.’ We really don’t know what some genes are doing, but that’s the kind of direction we want to go.”

By Nicole Frie, Monday, August 16, 2010

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