Inflammatory bowel disease (IBD) affects so many people from young to all stages in life, 1/250 people have IBD. When someone asks what causes it, we say “we think you have a genetic predisposition and that somehow alters the way your immune system responds to the environment including the microbes that are in your gut”. Having said that we do not really understand what that means, we cannot tell you what triggers the disease or what changes in the gut microbiome cause the disease, we know some genes are associated with increased risk but we are not even sure how those genes or defects in those genes lead to the disease. There are a lot of unknowns.