Navigation Links
New Gene Study of ADHD Points to Defects in Brain Signaling Pathways

PHILADELPHIA, Dec. 4, 2011 /PRNewswire-USNewswire/ -- Pediatric researchers analyzing genetic influences in attention-deficit/hyperactivity disorder (ADHD) have found alterations in specific genes involved in important brain signaling pathways. The study raises the possibility that drugs acting on those pathways might offer a new treatment option for patients with ADHD who have those gene variants—potentially, half a million U.S. children.

"At least 10 percent of the ADHD patients in our sample have these particular genetic variants," said study leader Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children's Hospital of Philadelphia. "The genes involved affect neurotransmitter systems in the brain that have been implicated in ADHD, and we now have a genetic explanation for this link that applies to a subset of children with the disorder."

The study appears online today in Nature Genetics.

ADHD is a common but complex neuropsychiatric disorder, estimated to occur in as many as 7 percent of school-age children and in a smaller percentage of adults. There are different subtypes of ADHD, with symptoms such as short attention span, impulsive behavior and excessive activity. Its causes are unknown, but it tends to run in families and is thought to be influenced by many interacting genes. Drug treatment is not always effective, particularly in severe cases.

The study team did whole-genome analyses of 1,000 children with ADHD recruited at The Children's Hospital of Philadelphia, compared to 4,100 children without ADHD. The researchers searched for copy number variations (CNVs), which are deletions or duplications of DNA sequences. They then evaluated these initial findings in multiple independent cohorts that included nearly 2,500 cases with ADHD and 9,200 control subjects. All the study subjects were children of European ancestry.

Among those cohorts, the research team identified four genes with a significantly higher number of CNVs in children with ADHD. All the genes were members of the glutamate receptor gene family, with the strongest result in the gene GMR5. Glutamate is a neurotransmitter, a protein that transmits signals between neurons in the brain. "Members of  the GMR gene family, along with genes they interact with, affect nerve transmission, the formation of neurons, and interconnections in the brain, so the fact that children with ADHD are more likely to have alterations in these genes reinforces previous evidence that the GRM pathway is important in ADHD," said Hakonarson. "Our findings get to the cause of the ADHD symptoms in a subset of children with the disease."

"ADHD is a highly heterogeneous disorder, and separating out the different subgroups of genetic mutations that these children have is very important," said co-first author Josephine Elia, M.D., a child psychiatrist at Children's Hospital and an ADHD expert. She added that thousands of genes may contribute to the risk of ADHD, but that identifying a gene family responsible for 10 percent of cases is a robust finding in a common neuropsychiatric disorder such as ADHD. Overall, according to the CDC, 5.2 million U.S. children aged 3 to 17 have been diagnosed with ADHD.

Elia said the fact that their study identified gene variants involved in glutamate signaling is consistent with studies in animal models, pharmacology and brain imaging showing that these pathways are crucial in a subset of ADHD cases. She added, "This research will allow new therapies to be developed that are tailored to treating underlying causes of ADHD. This is another step toward individualizing treatment to a child's genetic profile."

Hakonarson expects this study will set the stage for further discoveries of ADHD-related genes along GMR signaling pathways. Moreover, the current research strongly suggests that selective GRM agonists could be tested in clinical trials as a potential therapy for ADHD in patients harboring particular CNVs. He added that further preclinical studies must first be done to evaluate candidate drugs.

Joseph T. Glessner, a Ph.D. trainee at the Center for Applied Genomics, is also a co-first author of the study along with Elia. Other collaborators were from numerous U.S. and European centers. Funding for the study came from an Institutional Development Award to the Center for Applied Genomics from The Children's Hospital of Philadelphia. Funding also came from the National Institutes of Health, the Cotswold Foundation, a University of Pennsylvania National Center for Research Resources Clinical and Translational Science Awards grant, the U.S. Department of Health and Human Services, and other sources.

"Genome-wide copy number variation study associates metabotropic glutamate receptor gene networks with attention deficit hyperactivity disorder, Nature Genetics, advance online publication on Dec. 4, 2011. doi: 10.1038/ng.1013

About The Children's Hospital of Philadelphia: The Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals and pioneering major research initiatives, Children's Hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country, ranking third in National Institutes of Health funding. In addition, its unique family-centered care and public service programs have brought the 516-bed hospital recognition as a leading advocate for children and adolescents. For more information, visit

Contact: John Ascenzi
The Children's Hospital of Philadelphia
Phone: (267) 426-6055

SOURCE The Children's Hospital of Philadelphia
Copyright©2010 PR Newswire.
All rights reserved

Related medicine technology :

1. RECITAL Study Presents Excellent Outcomes and Rapid Patient Recovery With Revolutionary Femoral Access Procedure
2. Auxilium Pharmaceuticals, Inc. Announces First Patient Dosed in XIAFLEX® Study for Frozen Shoulder Syndrome
3. Ceregene Completes Enrollment of Second Phase 2 Study of CERE-120 for the Treatment of Parkinsons Disease
4. Merrimack Pharmaceuticals Initiates Enrollment in a Phase 1 Combination Study of MM-121 and Multiple Anticancer Therapies in Patients with Advanced Solid Tumors
5. BioMarin Initiates Phase 2 Study for GALNS in Patients Under Five Years of Age With MPS IVA
6. New Study Points to Novel Mechanism by Which Tumors Escape Recognition by the Immune System
7. Inspiration Biopharmaceuticals Initiates Second Pivotal Clinical Study of Innovative Hemophilia Therapy OBI-1
8. Cara Therapeutics Initiates Phase I Study with Oral Formulation of Novel Peripherally-Acting Kappa Opioid Agonist
9. Updated Survival Data from Study Comparing TTF™ (Tumor Treating Fields) Therapy to Best Standard Chemotherapy for Recurrent Glioblastoma Reported at the 16th Annual Scientific Meeting of the Society for NeuroOncology
10. Perceptive Informatics® Global Survey Results Indicate Wide Use of Industry-Standard Medical Imaging Metrics to Meet Study Milestones
11. Merrimack Pharmaceuticals Initiates Enrollment in Phase 2 Study of MM-121 in Combination with Erlotinib in Three Groups of Patients with Non-Small Cell Lung Cancer
Post Your Comments:
(Date:12/1/2015)... BANGALORE, India and ... (NASDAQ, TASE: MYL) today announced that it expects to ... for developing country markets funded by international donors, TLE400 ... + Efavirenz 400 mg) for $99 per patient, per ... (CHAI) to develop TLE400. The significantly reduced price could ...
(Date:12/1/2015)... , Dec. 1, 2015 Breg, Inc ... services, announced today that it has been awarded three ... Members served by Novation will have access to improved ... bracing products and soft goods dedicated to advancing orthopedic ... The aging U.S. population, rising prevalence of chronic ...
(Date:12/1/2015)... , Dec. 1, 2015 Building ... HIV/AIDS, Johnson & Johnson (NYSE: JNJ ) ... Janssen Pharmaceutical Companies to significantly reduce the burden ... make up 74 percent of new HIV infections ... on World AIDS Day, these new initiatives include ...
Breaking Medicine Technology:
(Date:12/1/2015)... ... December 01, 2015 , ... SAN FRANCISCO, ... announced that the organization has awarded Education and Developmental Therapies (EDT), an Applied ... The award celebrates exceptional special needs providers that excel in synthesizing the areas ...
(Date:12/1/2015)... ... ... Lutronic, a leading innovator of aesthetic and medical laser and energy-based technology, announced ... the United States. Clarity is a Superior Dual Wavelength Platform which combines two ... platform that is easy to own and operate. , For over a decade, ...
(Date:12/1/2015)... , ... December 01, 2015 , ... XTC Semifinals ... 10 semi-finalists to head to Las Vegas for CES 2016, the world’s largest Consumer ... of Consumer Technology Association Gary Shapiro, Founding Partner of Pacific Investments Veronica Serra, and ...
(Date:12/1/2015)... (PRWEB) , ... December 01, 2015 , ... Nurotron Biotechnology ... in its largest order to date. , The order will be from the ... Nurotron’s Venus Cochlear Implant System is an effective solution for children and adults suffering ...
(Date:12/1/2015)... (PRWEB) , ... December 01, 2015 , ... ... Contact Center Enterprise Authorized Technology Provider (ATP) status from Cisco. This designation recognizes ... and support Cisco Unified Contact Center solutions targeted to the high-end enterprise contact ...
Breaking Medicine News(10 mins):