Lab Report: Health, Science and Medicine

GENETICS

A Gene for Depression?

Your DNA provides powerful clues to understanding disease, but genes aren't destiny--particularly when it comes to mental illness. Researchers report that a particular gene may increase the risk of depression, but only in combination with an added, nongenetic factor--a stressful life event.

The scientists found that people with one form of a protein that ferries serotonin, a mood-related neurotransmitter, are especially prone to depression when faced with traumatic events, such as being diagnosed with a medical illness or being a victim of childhood abuse. The version of the gene that these individuals carry prevents nerve cells in the brain from reabsorbing serotonin, which leads to feelings of sadness and negative mood and may make it harder for them to recover emotionally from a crisis.

The results confirm earlier work that had linked the serotonin-transporter gene to depression under stressful circumstances, a connection that subsequent studies had questioned. The current analysis includes a broader range of study data, however, and appears to confirm the association.

CANCER

Scoping Out Cancer

It's not likely to make anyone's bucket list, but a colonoscopy could save you from needing to do everything on that list anytime soon. A new study confirms that regular colonoscopic screening, which involves inserting a scope through the rectum and into the intestines to detect and sometimes remove growths, can lower the risk of colon cancer by 77%. That number changes depending on the exact site of tumors: risk is reduced just 56% if the growth is on the right side of the intestines (which is harder to reach with the scope), but that's still a big improvement over people who did not get routine screenings.

Common wisdom calls for a colonoscopy once every 10 years for anyone over age 50, but that advice has been questioned by recent studies suggesting that the invasive and relatively expensive procedure does not find more tumors than less expensive tests that analyze fecal blood or use a shorter scope. The reason for the varying results may be operator skill; proper preparation and thorough execution of the test could improve its effectiveness.

For patients, it may be worth seeking out such skilled physicians, since colonoscopy is one of the few screening tools that can both detect precancerous growths and remove them, preventing cancer in a single procedure.

FROM THE LABS

Predicting IVF Success

In vitro fertilization (IVF) may be high-tech, but doctors still can't tell couples how likely it is that the procedure will yield a baby. Now a new probability calculating model that factors in the mother's age, the length of time the parents have been infertile and whether they had any previous live births via IVF may change that, letting potential parents know just how good their babymaking odds are. And for tech lovers: the model is also available as an iPhone app.

Hope Against Baldness