Genetic glitch increases men’s risk of impotence

Hope for new treatments

NEW YORK, Oct 9, (Agencies): Scientists say they’ve located the first well-documented genetic glitch that increases a man’s risk of impotence, a step that might someday lead to new treatments.

Most impotence isn’t caused by genetics but rather things like obesity, diabetes, heart disease, smoking, drug and alcohol use, stress or anxiety.

But in a study released Monday by the Proceedings of the National Academy of Sciences, researchers say they located a spot in human DNA where genetic variation might boost a man’s risk by about 25 percent.

They found statistical evidence for that by looking in the genetic makeup of about 36,600 men, and confirmed it in a similar study of 222,300 other men. Lab tests then suggested that variation might affect the activity of a nearby gene that’s known to be involved in sexual functioning.

Now scientists want to explore how such variation affects risk of the condition, said Eric Jorgenson, a researcher at Kaiser Permanente Northern California in Oakland and lead author of the paper. It may interfere with the functioning of certain brain circuits, he said.

He said discovering a biological explanation could give clues to developing new treatments for impotence, also known as erectile dysfunction.

Men who have a copy of this variant have a 26 percent increased risk of facing erectile dysfunction compared to the average population, said the findings in the Proceedings of the National Academy of Sciences.

Those with two copies of the variant face a 59 percent higher risk, according to geneticist Eric Jorgenson, the study’s lead author.

The average population risk is of one in five men, according to a 2007 study in the United States, but the ratio increases sharply with age.

About a third of erectile dysfunction risk is linked to genetic factors. According to the new study, the genetic variant Jorgenson and his colleagues identified alone accounts for two percent of the risk.

“We know that there are other factors for ED including smoking, obesity, diabetes and cardiovascular disease, and men who address those factors can reduce their risk of ED,” Jorgenson told AFP.

“Because the region that we identified in the human genome appears to act independently of those risk factors, developing new treatments that target the variation in this genetic location has the potential to help those men who do not respond to current treatment.”