Navigation Links
New Clues to Possible Genetic Basis for ADHD

By Steven Reinberg
HealthDay Reporter

MONDAY, Oct. 4 (HealthDay News) -- Children whose mothers are likely to produce too little of the brain chemical serotonin because of gene mutations may be at higher risk of developing attention-deficit hyperactivity disorder (ADHD) later in life, Norwegian researchers report.

Serotonin is involved in many physiological functions and plays an important role during development, especially in the development of nerve cells, the researchers say.

"An impaired maternal serotonin production may have profound long-term behavioral effects on [offspring], independent of the children's own genotypes," said lead researcher Dr. Jan Haavik, from the Department of Biomedicine at the University of Bergen.

"As technologies evolve, systematic gene sequencing can provide new insight into mechanisms of complex disorders like ADHD," he added.

The report is published in the October issue of the Archives of General Psychiatry.

For the study, Haavik and colleagues took blood samples from 495 adults with ADHD and 97 of their family members as well as from 187 people without ADHD from across Norway. In addition, they collected data on these individuals' psychiatric diagnoses and symptoms.

The researchers then sequenced the genes of 646 of the participants and found nine mutations, eight of which were linked to the two enzymes involved in the body's synthesis of serotonin.

The researchers found that children of mothers who were predisposed to impaired serotonin production were more likely to have ADHD. Among 38 family members and 41 of the children, those whose mother had one of the mutations had a 1.5 to 2.5 higher risk of developing ADHD, compared with people or children who did not have these mutations or children whose father had the mutations.

The number and severity of ADHD symptoms varied widely, which suggested that for children of mothers with these mutations, "the clinical outcome probably depends on a sum of many different genetic or environmental factors in addition to variations in maternal serotonin levels," the Norwegian researchers noted.

They also stressed that further studies replicating the results, "preferably in larger samples, will be required to corroborate this relationship."

Dr. Stephan Zuchner, an associate professor and director of the Center for Human Molecular Genomics at the University of Miami Miller School of Medicine, said there is considerable debate of how much of ADHD is genetically based.

"There is an extreme spectrum, from people who think it's not so much to people who think it's a lot," he said. "I think it's certainly significant -- the genetic contribution. There is little doubt that ADHD has a genetic component."

However, Zuchner thinks that developing ADHD is a result of both genetics and environment. "It is rare to see that genetics alone can cause ADHD," he said.

Zuchner also noted this is a small study, so it is premature to try to identify the risk of developing ADHD based on these genetic mutations. "I would be careful from this small study not to draw any larger conclusions," he said.

At least one other study has found some evidence of a genetic basis for ADHD.

A report in the Sept. 30 online edition of The Lancet found that many who suffer from ADHD appear to have a genetic abnormality that may predispose them to the condition, British researchers report.

The U.K. team analyzed the genetic information of 366 children with ADHD, comparing it to more than 1,000 unrelated but ethnically matched individuals in a control group. Children with ADHD were significantly more likely to have missing or duplicated segments of DNA -- called copy number variations (CNVs) -- than were children without ADHD, the researchers found. This type of genetic variation is more common in those with brain disorders, they noted.

The findings were replicated in a study of 825 Icelandic patients with ADHD and more than 35,000 Icelandic control group members.

In background materials to the study, the British researchers said they hoped their findings would help overcome the stigma associated with ADHD -- which some people associate with parenting problems or poor diet -- by suggesting that it has a genetic basis.

Finally, a third study - this time a small case-control study of about 250 children -- found that children with ADHD are more likely to suffer from depression or attempt suicide as teens.

In fact, 16 to 37 percent of those with ADHD suffer from major depressive disorder or a relatively mild form of depression known as dysthymia, noted Andrea Chronis-Tuscano of the University of Maryland and colleagues.

"These findings suggest that it is possible to identify children with ADHD at very young ages who are at very high risk for later depression and suicidal behavior," the authors wrote in the same issue of The Lancet. "Considered in light of what is already known about the antisocial outcomes of childhood ADHD and their risk for unintentional injury, it would not be premature to test early prevention programs designed to reduce both serious behavioral and affective [consequences] of ADHD in early childhood."

More information

For more information on ADHD, visit the U.S. National Institute of Mental Health.

SOURCES: Jan Haavik, M.D., Ph.D., department of biomedicine, University of Bergen, Norway; Stephan Zuchner, M.D., associate professor, director, Center for Human Molecular Genomics, University of Miami Miller School of Medicine; Oct. 2010, Archives of General Psychiatry

Copyright©2010 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. New Clues to Treating Ovarian Cancer Relapse
2. Hurts so good -- neural clues to the calming effects of self-harm
3. Long-Term Type 1 Diabetes Survivors Give Clues to the Disease
4. More Clues To Fibromyalgia Pain
5. Gene Mutation Offers Clues to Tamoxifen-Blood Clot Link
6. New Clues for Treating Ulcerative Colitis
7. Gene Mutations Offer Clues to Autoimmune Disorders
8. Cysts hold clues to pancreatic cancer
9. Tracking PSA Test Results Over Time Gives Clues to Cancer
10. New Clues to Treating Immune System Disorders
11. New Clues to Treating an Aggressive Breast Cancer
Post Your Comments:
Related Image:
New Clues to Possible Genetic Basis for ADHD
(Date:6/25/2016)... ... June 25, 2016 , ... Dr. Calvin ... injury. Recently, he has implemented orthobiologic procedures as a method for treating his ... of the first doctors to perform the treatment. Orthobiologics are substances that orthopaedic ...
(Date:6/24/2016)... ... , ... A recent article published June 14 on E Online ... on to state that individuals are now more comfortable seeking to undergo not only ... calf and cheek reduction. The Los Angeles area medical group, Beverly Hills Physicians (BHP) ...
(Date:6/24/2016)... , ... June 24, 2016 , ... Marcy was in a crisis. Her son James, ... out at his family verbally and physically. , “When something upset him, he couldn’t control ... use it. He would throw rocks at my other children and say he was going ...
(Date:6/24/2016)... ... June 24, 2016 , ... Dr. Amanda Cheng, an ... Dr. Cheng has extensive experience with all areas of orthodontics, including robotic Suresmile ... orthodontics. , Micro-osteoperforation is a revolutionary adjunct to orthodontic treatment. It can ...
(Date:6/24/2016)... ... June 24, 2016 , ... People across the U.S. are sharpening their pencils ... an essay contest in which patients and their families pay tribute to a genetic ... 2016 National Society of Genetic Counselors (NSGC) Annual Education Conference (AEC) this September. ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... , June 23, 2016  MedSource announced ... as its e-clinical software solution of choice.  This ... best possible value to their clients by offering ... The preferred relationship establishes nowEDC as the EDC ... for MedSource,s full-service clients.  "nowEDC has long been ...
(Date:6/23/2016)... INDIANAPOLIS , June 23, 2016 Roche ... received 510(k) clearance for its Elecsys BRAHMS PCT (procalcitonin) ... severe sepsis or septic shock. With this clearance, Roche ... provide a fully integrated solution for sepsis risk assessment ... associated with bacterial infection and PCT levels in blood ...
(Date:6/23/2016)... Calif. , June 23, 2016 ... CST on Thursday, July 7, 2016 , , , , ... ) , , , , EXPERT PANELISTS:  , , ... Naik; Senior Industry Analyst, Christi Bird; Senior Industry Analyst, Divyaa Ravishankar ... The global pharmaceutical industry is witnessing an exceptional ...
Breaking Medicine Technology: