The genes are located on the chromosome 2The statistics show that 4.6 % of the Americans with ages between 15 and 54 have tried to take their lives.
That's why researchers want to see if there is a genetic factor in this tendency.
A new research made at Johns Hopkins University has discovered evidence of a genetic tendency toward suicide, and the gene/genes responsible would be located on the chromosome 2. "We're hoping our findings will eventually lead to tests that can identify those at high risk for attempting suicide," said Dr. Virginia Willour, an assistant professor in the Department of Psychiatry at the Johns Hopkins University School of Medicine and lead author of the study.
The researchers investigated genetic matches in families whose members were known for a history of bipolar disorder and attempted suicide.
The same stretch on chromosome 2 was recently found as carrying the genetic factor by two complementary family studies that investigated attempted suicide in families with major depression and alcohol dependence. "Family linkage studies are not always consistent, so the fact that all three studies, including ours, point to the same region of the genome is a good indication that we are on the right track toward identifying a gene or genes that play a role in why a person chooses to take his or her own life," said Willour.
"The researchers examined data from 162 families with bipolar disorder. They looked at attempted suicide in this sample because it is an important clinical problem that tends to occur more often in some of these families than in others, suggesting a distinctive genetic basis," said senior author James B. Potash, M.D., M.P.H., of the Department of Psychiatry at Hopkins.
From the 162 investigated families, the team selected 417 subjects diagnosed with schizoaffective/bipolar disorder, bipolar I disorder or bipolar II disorder. These subjects were asked whether they had ever attempted suicide and the degree of intent of the most serious attempt. 154 individuals were found to have attempted suicide, and 122 intended to do it.
A computer analysis located the genetic similarities between subjects with similar psychological profiles. Individuals with a history of attempted suicide and bipolar disorder presented a high level of genetic match at the DNA marker D2S1777 on the region 2p12 of chromosome 2.
A close marker, D2S1790, located in the 2p11 region of chromosome 2 was found in a 2004 research at the University of Connecticut School of Medicine, investigating the link between alcoholism and attempted suicide.
The next task of the researchers is to locate the specific genes responsible for the increased tendency to commit suicide. "Once we have located the specific gene, we can better identify people who might be at risk of suicide and offer drug companies a target for possible therapies." said Willour.