iceberg disease
n.— «Experts commonly refer to it as an “iceberg” disease. Visible at the tip are individuals whose symptoms include diarrhea, abdominal pain, weight loss and, in children, delayed growth. The rest of the iceberg consists of those with more subtle symptoms, such as bloating or excess gas. Although these may go unrecognized as signs of celiac disease, the damage continues.» —“Celiac disease: an elusive ‘iceberg’” by Leslie Beck Globe and Mail (Toronto, Canada) July 9, 2008. (source: Double-Tongued Dictionary)