Coeliac isease (pronounced /ˈsiːliːˌæk/), also spelled celiac disease, is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy. Symptoms include chronic diarrhoea, failure to thrive (in children), and fatigue, but these may be absent and symptoms in all other organ systems have been described. It is estimated to affect about 1% of all Indo-European populations, but is thought to be significantly underdiagnosed. A growing portion of diagnoses are being made in asymptomatic persons as a result of increased screening.