Featured Research

from universities, journals, and other organizations

Schizophrenia Gene Variant Linked To Risk Traits

Date:
August 13, 2004
Source:
NIH/National Institute Of Mental Health
Summary:
Researchers at the NIH's National Institute of Mental Health (NIMH) have identified a relationship between a small section of one gene, the brain chemical messenger glutamate, and a collection of traits known to be associated with schizophrenia.

Researchers at the NIH's National Institute of Mental Health (NIMH) have identified a relationship between a small section of one gene, the brain chemical messenger glutamate, and a collection of traits known to be associated with schizophrenia. The finding confirms the gene responsible for management of glutamate is a promising candidate in determining risk for schizophrenia. The study, conducted by Michael Egan, M.D., Daniel Weinberger, M.D., and colleagues, is published in the August 9, 2004, of the Proceedings of the National Academy of Sciences.

Glutamate is a key neurotransmitter long thought to play a role in schizophrenia. The gene identified in this study makes the glutamate receptor (GMR3) which is responsible for regulating glutamate in synapses—spaces in between brain cells"—"where chemicals like glutamate transfer information from cell to cell. The amount of glutamate remaining in the synapse may have a downstream impact on cognition.

"Because of the small effects of individual genes in complex genetic disorders like schizophrenia, it is difficult to make significant associations with any one particular marker. However, this study brings us closer to unlocking the genetic clues that increase the risk for schizophrenia," said NIMH Director Thomas R. Insel, M.D.

Researchers know that schizophrenia affects several regions in the front part of the brain that are involved in higher order thinking and decision-making and neurotransmitter systems like glutamate. Many of the genes already identified as likely candidates for the disorder have been thought to affect the glutamate system. The study implicates the GMR3 gene as well.

GRM3 alters glutamate transmission, brain physiology and cognition, increasing the risk for schizophrenia. To pinpoint the section of the gene responsible for these changes, scientists are exploring a region where the gene may differ by one-letter at a location called SNP4. The normal variation is spelled with either an 'A'-the more common of the two-or a 'G'. Patients with schizophrenia are more likely to inherit an 'A' from either parent, indicating the 'A' variant slightly increases risk. The 'A' variant is also associated with the pattern of traits linked with the disorder. This was true in patients, their healthy siblings, and normal volunteers.

In the study, people with an 'A' variant have differences in measures of brain glutamate. In a postmortem study of brain tissue, the 'A' variant was associated with lower levels of the chemical that promotes gene expression for the protein responsible for regulating the level of glutamate in the cell. N-acetylaspartate, a measure of cell health evaluated through the use of MRI spectroscopy, was lower in 'A' participants. 'A' carriers had poorer performance on several cognitive tests of prefrontal and hippocampal function than people with the 'G' variant. The 'G' marker was associated with relatively more 'efficient' processing in the prefrontal cortex. Those who inherit the 'G' variant scored higher on verbal and cognitive tests than those who have two of the 'A' variant. Scientists think the less common 'G' variant may exert a protective effect against the disease.

People with schizophrenia and their healthy siblings share the inefficient brain physiology, and cognition patterns, which suggests a link to genetic risk, though the disease itself is most likely caused by a combination of genetic and environmental factors. The gene seems to affect the mechanism of memory encoding only as there was no genotype effect seen during retrieval in the memory tests.

Although scientists could not be certain that the 'A/G' difference accounts for all the affects on brain function, there may be yet undiscovered variations located near SNP4 on the GRM3 gene. It is unclear as to why the higher-risk 'A' variant is more common in humans. Researchers speculate that it may provide a counterbalancing advantage, perhaps related to reduced glutamate in the cells.


Story Source:

The above story is based on materials provided by NIH/National Institute Of Mental Health. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute Of Mental Health. "Schizophrenia Gene Variant Linked To Risk Traits." ScienceDaily. ScienceDaily, 13 August 2004. <www.sciencedaily.com/releases/2004/08/040812072208.htm>.
NIH/National Institute Of Mental Health. (2004, August 13). Schizophrenia Gene Variant Linked To Risk Traits. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2004/08/040812072208.htm
NIH/National Institute Of Mental Health. "Schizophrenia Gene Variant Linked To Risk Traits." ScienceDaily. www.sciencedaily.com/releases/2004/08/040812072208.htm (accessed April 23, 2014).

Share This



More Mind & Brain News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Smaller Plates And Cutlery Could Make You Feel Fuller

How Smaller Plates And Cutlery Could Make You Feel Fuller

Newsy (Apr. 22, 2014) NBC's "Today" conducted an experiment to see if changing the size of plates and utensils affects the amount individuals eat. Video provided by Newsy
Powered by NewsLook.com
Do We Get Nicer With Age?

Do We Get Nicer With Age?

Newsy (Apr. 22, 2014) A recent report claims personality can change over time as we age, and usually that means becoming nicer and more emotionally stable. Video provided by Newsy
Powered by NewsLook.com
How to Master Motherhood With the Best Work/Life Balance

How to Master Motherhood With the Best Work/Life Balance

TheStreet (Apr. 22, 2014) In the U.S., there are more than 11 million couples trying to conceive at any given time. From helping celebrity moms like Bethanny Frankel to ordinary soon-to-be-moms, TV personality and parenting expert, Rosie Pope, gives you the inside scoop on mastering motherhood. London-born entrepreneur Pope is the creative force behind Rosie Pope Maternity and MomPrep. She explains why being an entrepreneur offers the best life balance for her and tips for all types of moms. Video provided by TheStreet
Powered by NewsLook.com
Sorry, Guys, Only Women Can Make Their Voices Sound Sexier

Sorry, Guys, Only Women Can Make Their Voices Sound Sexier

Newsy (Apr. 21, 2014) According to researchers at Albright College, women have the ability to make their voices sound sexier, but men don't. Video provided by Newsy
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:
from the past week

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