Gene: Depression

Source: The Anxiety of Depression, 17-07-2003

In a 26-year study of the genetic profiles and hardships of 847 New Zealanders, researchers found that people with one version of a specific gene were protected from falling into depression, while those with another variation became depressed twice as often.

Individuals with the “long” version of the gene, which regulates serotonin, could cope with challenges such as the death of family a member, a major breakup or getting fired. People with the “short” version of the gene were much more likely to fall into depression following a major life crisis.

“Tests showed that life events led to new onset of depression among people who had the stress-sensitive gene, but who did not have depression before their life events happened,” said Terrie Moffitt, a professor at the Institute of Psychiatry in London and lead researcher on the international research team.

One possible complication is that the gene that was the subject of the study, called 5-HTT, are likely working together with other gene variations. However, considerable evidence points to the short and long versions of 5-HTT as determinants of how we’ll handle seriously bad life events.

More here.

On the other hand, another group of scientist found the genes related to depression, according to this article.

Some people appear to be genetically predisposed to developing severe depression, but researchers have yet to pin down the genes responsible. Now, a specific region rife with promise has been located on one chromosome by a consortium of researchers working under Douglas Levinson, MD, professor of psychiatry and behavioral sciences at the Stanford University School of Medicine.

Levinson’s group, comprising researchers from six universities, achieved this breakthrough by studying 650 families in which at least two members suffered from repeated bouts of severe depression that began in childhood or early adult life. The first of the studies was a genome-wide scan that looked for evidence of genetic “linkage” within families between depression and DNA markers on the various chromosomes. The linkage study identified regions worthy of more intensive examination.

The second study was a more detailed look at the most suspicious of these regions, located on chromosome 15. Levinson said the team studied six DNA markers in this region in the first study, and an additional 88 in the second. “We found highly significant evidence for linkage to depression in this particular part of chromosome 15,” he said. “This is one of the strongest genetic linkage findings for depression so far.”

However, there is more gene invloved for women who are prone to feel depression than men, according to this report:

About half the risk of depression is thought to be genetic. The single gene, 5-HTT, that has been definitively linked to depression is no more common in women than in men. But preliminary research suggests that there are other depression-related genes that mainly affect women.

For example, after scanning the genomes of people with major depression in 81 families, Dr. George Zubenko, a professor of psychiatry at the University of Pittsburgh School of Medicine, identified 19 regions of chromosomes that were especially common and, therefore, likely to contain genes that promote depression. Four of these regions showed up only in the women and one only in the men, Dr. Zubenko and his colleagues reported last July in The American Journal of Medical Genetics, an online publication.

Such findings suggest that more genes may help to set off depression in women than in men, Dr. Zubenko said, explaining in part why more women become depressed. One may be CREB1, a gene that Dr. Zubenko’s group has identified as a strong candidate. Especially intriguing, Dr. Zubenko said, is that CREB1 interacts with estrogen receptors.

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