Celiac disease is a chronic autoimmune disorder where the ingestion of gluten—a protein found in wheat, barley, and rye—triggers an immune response that damages the small intestine. This condition affects the lining of the small intestine, leading to malabsorption of nutrients and a variety of gastrointestinal and systemic symptoms. Celiac disease can occur at any age and is often inherited, meaning it tends to run in families.