Celiac disease is an immune system disorder in genetically predisposed people that results in damage to the lining of the small intestine when foods with gluten are eaten. The risk for the disease may be inherited, since about 10% of first-degree relatives (mother, father, brother, sister, son, or daughter) of people who have celiac disease also develop the condition. In people who are genetically predisposed, celiac disease may be triggered by environmental factors, including viral and bacterial infections.

People who have celiac disease are also more likely than others to have:

• Dermatitis herpetiformis (more common in adults but can occur in children).
• Osteoporosis.
• Type 1 diabetes (insulin-dependent diabetes).
• Autoimmune thyroid disease.
• Down syndrome.
• Sjögren's syndrome.
• Selective antibody deficiency (immunoglobulin A [IgA] deficiency).
• Iron deficiency anemia or folic acid deficiency anemia.