Identical twins not as identical as believed

February 16, 2008

http://www.physorg.com/news122300048.html

Contrary to our previous beliefs, identical twins are not genetically identical. This surprising finding is presented by American, Swedish, and Dutch scientists in a study being published today in the prestigious journal American Journal of Human Genetics. The finding may be of great significance for research on hereditary diseases and for the development of new diagnostic methods.

How can it be that one identical twin might develop Parkinson’s disease, for instance, but not the other? Until now, the reasons have been sought in environmental factors. The current study complicates the picture.

“Even though the genome is virtually identical in identical twins, our results show that there in fact are tiny differences and that they are relatively common. This could have a major impact on our understanding of genetically determined disorders,” says Jan Dumanksi, who co-directed the international study with his colleague Carl Bruder. “By uncovering these small genetic differences in identical twins where one of them is sick, we have a way of tying specific genetic changes to the genesis of common diseases,” says Carl Bruder. These researchers studied 19 pairs of identical twins and found that they indeed had the same DNA but nevertheless evinced differences in the number of copies of individual DNA segments. A segment might be missing, or more copies might exist in one twin. This could explain how one identical twin can be afflicted with a disorder while the other twin remains fully healthy, according to the scientists. Source: Uppsala University

» Next Article in Medicine & Health - Genetics: Metabolic syndrome linked to cold tolerance

Flavonoids in orange juice make it a healthy drink, despite the sugar

http://www.physorg.com/preview103902022.html

more

Orange juice, despite its high caloric load of sugars, appears to be a healthy food for diabetics due to its mother lode of flavonoids, a study by endocrinologists at the University at Buffalo has shown. The study appeared in the June 2007 issue of Diabetes Care. Full story »

San Diego battles rising STD cases

http://www.physorg.com/news122303610.html

Health officials in San Diego have begun a media campaign to try to cut the rising rate of syphilis and other sexually-transmitted diseases.

San Diego County health officials recorded 312 new syphilis cases last year, up from 23 a decade ago. Chlamydia and gonorrhea cases in San Diego County also have increased, the San Diego Union-Tribune said Thursday. Officials said they aren't sure why the rates are jumping so high. "A possible explanation for the increase in gonorrhea, Chlamydia and syphilis cases could be that patients are not forthcoming about their sexual practices, making it difficult for their health providers to order appropriate tests," county health officials said in a statement. The newspaper said 2005 statistics showed that about eight of every 10 syphilis cases in San Diego County were diagnosed in men who had sex with men.