Autoimmune disease affects up to 50 million people worldwide. An autoimmune disease develops when your immune system, which defends your body against disease, decides your healthy cells are foreign. As a result, your immune system attacks healthy cells. Depending on the type, an autoimmune disease can affect one or many different types of body tissue. It can also cause abnormal organ growth and changes in organ function.
There are as many as 80 types of autoimmune diseases. Many of them have similar symptoms, which makes them very difficult to diagnose. It’s also possible to have more than one at the same time. Autoimmune diseases usually fluctuate between periods of remission (little or no symptoms) and flare-ups (worsening symptoms). Currently, treatment for autoimmune diseases focuses on relieving symptoms because there is no curative therapy. Autoimmune diseases often run in families, and 75 percent of those affected are women.
The following are some of the more common autoimmune diseases:
- rheumatoid arthritis: inflammation of joints and surrounding tissues
- systemic lupus erythematosus: affects skin, joints, kidneys, brain, and other organs
- celiac sprue disease: a reaction to gluten (found in wheat, rye, and barley) that causes damage to the lining of the small intestine
- pernicious anemia: decrease in red blood cells caused by inability to absorb vitamin B-12
- vitiligo: white patches on the skin caused by loss of pigment
- scleroderma: a connective tissue disease that causes changes in skin, blood vessels, muscles, and internal organs
- psoriasis: a skin condition that causes redness and irritation as well as thick, flaky, silver-white patches
- inflammatory bowel diseases: a group of inflammatory diseases of the colon and small intestine
What role does our genetic makeup play in autoimmune diseases?
Researchers found that 89 independent variations in human genetics that are believed to be responsible for autoimmune conditions, from celiac disease and multiple sclerosis to rheumatoid arthritis and asthma. Understanding how these mechanisms work could help scientists to develop new treatments.
A mutation in the ADAR1 gene causes a defect in an “alarm system” in cells that normally protects the body from viruses and other infections by triggering the body’s immune system to fight. The mutation causes this alarm system to be tripped by the cell’s own molecules, causing the immune system to attack – the uniting trait of all autoimmune diseases.
The ADAR1 mutation and the others identified by the researchers together helped reveal the system that helps the body to differentiate between normal RNA and RNA from foreign organisms. The exact problem with this mechanism that characterizes autoimmune disorders differs for each, as the body’s way of attacking itself is unique and presents no two symptoms that are exactly alike, even within families.
Though autoimmune diseases vary wildly in their specifics, a family history of autoimmune disorders can indicate a genetic predisposition that may increase the risk to develop an autoimmune disease. While diseases can be passed down from parent to child, it doesn’t automatically mean someone will get the same disorders their family members suffer from. The exact nature of the immune response and how the body deals with it varies from case to case.
Finding the ADAR1 mutation is a huge step toward learning more about autoimmune diseases and what exactly they do to the human body when active. Mapping the relevant mutations and their chemical signatures in the body helps reveal the exact mechanisms by which autoimmune diseases occur and cause harm – hopefully providing new targets for doctors trying to treat these stubborn and pernicious disease.