Similarly, in cancer the epigenetic variation across different cells of the same tissue may explain why only some cells of prostate or breast or some other tissue become malignant while others remain normal.

"During the maturation of sperm and egg cells, epigenetic signatures are reprogrammed, which seems to result in a pretty high error rate," Dr. Petronis says. "Such common epigenetic mutations may explain one of the evolutionary mysteries - why rates of conditions such as autism and schizophrenia are not decreasing, despite the fact that individuals affected with these conditions have fewer children. Classic evolutionary theory tells us that these conditions should disappear, but this is not happening," he says. The rate of schizophrenia remains steady at about 1% of the population, and rates of autism may actually be increasing.

If epigenetic origin of human disease is proven, the idea of "switching off" epigenetic risk factors can largely substitute the older notion that science could fix a "bad" gene by replacing it, says Dr. Petronis. "The future of epigenetic therapy offers much more exactitude and safety," he says. Epigenetics research holds promise in dozens of complex traits and diseases such as cancers, mental illness, asthma, Parkinson's disease, diabetes, and multiple sclerosis. "Right now we develop treatments for a disease based on what we know about the average person, or the population as a whole. But epigenetics will help us to realize our goal of a truly personalized medicine," he adds.

Source: CENTRE FOR ADDICTION AND MENTAL HEALTH