Autoimmune diseases, like multiple sclerosis and lupus, occur when your immune system goes haywire and starts targeting your own body. These diseases affect women at much higher rates than men. Up to now, the reason why has been a mystery. A group of scientists from Stanford recently found that the cause may lie in the X chromosome, with a molecule called Xist. In female cells that have two X chromosomes (XX), Xist plays a key role to deactivate one X chromosome so that there’s only one X used. In male cells, which only have one X chromosome (XY), Xist is completely inactive. These researchers discovered that Xist itself can cause an autoimmune response.
