Featured Research

from universities, journals, and other organizations

Attention-Deficit Hyperactivity Disorder Related To Advantageous Gene

Date:
January 9, 2002
Source:
University Of California, Irvine
Summary:
A variant form of a gene associated with attention-deficit hyperactivity disorder (ADHD) indicates that the disorder is a recent affliction and may once have helped humans thrive and survive, according to a UCI College of Medicine study.

Irvine, Calif., Jan. 8, 2002 -- A variant form of a gene associated with attention-deficit hyperactivity disorder (ADHD) indicates that the disorder is a recent affliction and may once have helped humans thrive and survive, according to a UCI College of Medicine study.

Related Articles


The human gene study, which appears in the Jan. 8 issue of Proceedings of the National Academy of Science, suggests that behavior now considered inappropriate in a classroom may be related to behavior that once helped humans overcome their environment.

Robert Moyzis, professor of biological chemistry, and his colleagues studied genes from 600 individuals worldwide. Among numerous new genetic variations of the receptor for the dopamine neurotransmitter, they found one linked strongly to both ADHD and a behavior trait called "novelty seeking," a condition often underlying addiction. Their analysis of the genetic variations also suggests that this variation occurred recently in human evolution between 10,000 and 40,000 years ago.

"We found a significant positive selection for the genetic variation associated with ADHD and novelty-seeking behavior in the human genome," Moyzis said. "This study strengthens significantly the connection between genetic variations and ADHD. It also provides a clue as to why ADHD is so pervasive and may show us a way to provide more effective treatments."

The researchers found 56 variations, or alleles (al-LEELEs) of a gene called DRD4, which produces the receptor for dopamine, a neurotransmitter. One allele, known as 7R, was strongly associated with ADHD. By analyzing the variations in DRD4, they also found that the 7R allele was created recently and may have provided an evolutionary advantage at some time in human history. The study could not determine, however, if that evolutionary selection is still occurring.

Brain cells signal each other with a number of neurotransmitters, including dopamine. The dopamine system, among other things, controls movement behavior and may be involved in learning and responding to psychological rewards. It also has been implicated in addictive behavior.

ADHD is the most common disorder in early childhood, affecting about 3 percent of all elementary school children in the United States. The disorder is marked by developmentally inappropriate conduct, lack of attention, impulsive and hyperactive behavior, all occurring before a child becomes 7 years old. Approximately half of children with ADHD have the 7R allele.

Between 10,000 and 40,000 years ago, anthropologists concur that humans were developing the first signs of complex societies, replete with agriculture, rudimentary governments and the creation of cities for the first time. Humans also were rapidly expanding and exploring the planet. These revolutionary changes in human societies may have changed the forces that selected for certain genetic traits.

"Our data show that the creation of the 7R allele was an unusual, spontaneous mutation, which became an advantage for humans," Moyzis said. "Because it was an advantage, the gene became increasingly prevalent. This is very different from other genes that predispose to genetic disorders, where the mutations are detrimental. We believe this helps explain why a disorder with such a strong genetic association is so common today."

The researchers are now working on determining how the genetic variations in DRD4 may actually predispose individuals to ADHD and other behaviors, and on examining the relationship between other complex genetic variations and ADHD.

Moyzis's colleagues include Yuan-Chun Ding, Han-Chang Chi, Deborah Grady, Pam Flodman, M. Anne Spence, Sabrina Schuck and James Swanson of UCI; Ya-Ping Zhang of the Chinese Academy of Sciences, Kunming, China; and Atsuyuki Morishima, Judith Kidd and Kenneth Kidd of Yale University.

The study was supported by grants from the U.S. Department of Energy and the National Institute of Mental Health.


Story Source:

The above story is based on materials provided by University Of California, Irvine. Note: Materials may be edited for content and length.


Cite This Page:

University Of California, Irvine. "Attention-Deficit Hyperactivity Disorder Related To Advantageous Gene." ScienceDaily. ScienceDaily, 9 January 2002. <www.sciencedaily.com/releases/2002/01/020109074512.htm>.
University Of California, Irvine. (2002, January 9). Attention-Deficit Hyperactivity Disorder Related To Advantageous Gene. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2002/01/020109074512.htm
University Of California, Irvine. "Attention-Deficit Hyperactivity Disorder Related To Advantageous Gene." ScienceDaily. www.sciencedaily.com/releases/2002/01/020109074512.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
Dads-To-Be Also Experience Hormone Changes During Pregnancy

Dads-To-Be Also Experience Hormone Changes During Pregnancy

Newsy (Dec. 18, 2014) A study from University of Michigan researchers found that expectant fathers see a decrease in testosterone as the baby's birth draws near. Video provided by Newsy
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
UN: Up to One Million Facing Hunger in Ebola-Hit Countries

UN: Up to One Million Facing Hunger in Ebola-Hit Countries

AFP (Dec. 17, 2014) Border closures, quarantines and crop losses in West African nations battling the Ebola virus could lead to as many as one million people going hungry, UN food agencies said on Wednesday. Duration: 00:52 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins