The study sheds light on why the same disease often strikes males and females differently, and why the genders may respond differently to the same drug. "We previously had no good understanding of why the sexes vary in their relationship to different diseases," explained Xia Yang, Ph.D., first author and postdoctoral fellow in cardiology at the David Geffen School of Medicine at UCLA. "Our study discovered a genetic disparity that may explain why males and females diverge in terms of disease risk, rate and severity."

"This research holds important implications for understanding disorders such as diabetes, heart disease and obesity, and identifies targets for the development of gender-specific therapies," said Jake Lusis, Ph.D., co-investigator and UCLA professor of human genetics. The UCLA team examined brain, liver, fat and muscle tissue from mice with the goal of finding genetic clues related to mental illnesses, diabetes, obesity and atherosclerosis. Humans and mice share 99 percent of their genes.

The scientists focused on gene expression. The team scrutinised more than 23,000 genes to measure their expression level in male and female tissue. While each gene functioned the same in both sexes, the scientists found a direct correlation between gender and the amount of gene expressed. "Males and females share the same genetic code, but our findings imply that gender regulates how quickly the body can convert DNA to proteins," said Yang. "This suggests that gender influences how disease develops."

"Our findings in the liver may explain why men and women respond differently to the same drug," Lusis added. "Studies show that aspirin is more effective at preventing heart attack in men than women. One gender may metabolise the drug faster, leaving too little of the medication in the system to produce an effect."

MEDICA.de; Source: University of California, Los Angeles (UCLA)