EVA BUTO
Science Editor
evie@psu.edu

Autoimmune diseases affect between 21 and 49 million Americans and are defined as a disorder that causes the immune system to attack the body instead of foreign contaminants. Well-known autoimmune diseases include celiac disease, lupus, Grave’s disease, and arthritis. Another fact about autoimmune diseases is that they are predominantly found in women, who make up up to 80% of autoimmune disease sufferers. This has been a barrier for sufferers of autoimmune disorders, as women as a whole are more likely to experience medical discrimination. However, it was still unknown why mainly women get these disorders. However, scientists now have a theory. 

For most humans, a man has an X and Y chromosome, while women have two X chromosomes. According to a study published by Diana Dou, Yanding Zhao, and many other scientists in the journal Cell, intersex males with the chromosome arrangement XXY are as likely to experience autoimmune disease as women are. People with Klinefelter syndrome are phenotypically male and have male hormones and sexual development. The fact that they are just as likely to experience autoimmune disease points to the issue being with the second X chromosome itself and therefore, a hypothesis was born. 

All humans need an X chromosome, but they only need one. In women, this second X chromosome is silenced by a nucleotide called Xist, which is necessary for normal development. This may however be a double-edged sword. In 2015, a scientist studying autoimmune diseases found that many of the molecules that facilitate Xist are also likely culprits in the development of autoimmune disorders.

In order to test this hypothesis, scientists genetically engineered male rats to produce Xist as well as the females. Not only were male rats more susceptible to autoimmune diseases, they also suffered from worse affects than infected females. This links autoimmune disease directly to the suppression of the X chromosome. It is still unknown exactly what causes this: some scientists believe that autoimmune diseases can develop when too much waste Xist is released from dying cells into the bloodstream. Once these are attacked by the body, it may cause the body to start attacking healthy cells. 

Overall, the news that scientists are working to find the mechanisms behind autoimmune disease is encouraging. Currently, no autoimmune disease is considered curable. Although symptoms can be managed, people who have these disorders have to manage them for the rest of their lives. Many conditions can cause pain or difficulty carrying out day-to-day activities, and some can even result in premature death. The first step of developing a treatment for these disorders is to understand how they operate.