Although the exact cause of celiac disease isn't known, having certain genes increases your risk. You are more likely to have these genes if you have a first-degree relative (mother, father, brother, sister, son, or daughter) who has celiac disease.
Environmental factors, such as infections, may trigger changes in the small intestine of a person with these genes. Then, eating foods that contain gluten can trigger an abnormal immune system response. Over time, this response can cause digestion and absorption problems.