Type 1 Diabetes
T1D or juvenile diabetes is a autoimmune disease in which a person's pancreas stops producing insulin, a hormone that enables people to get energy from food.
How it happens is the pancreas stops producing insulin. Some signs/symptoms are increased thirst, frequent urination, hunger, fatigue, and blurred vision. The cause of T1D are unknown the treatments are maintaining normal blood sugar levels through regular monitoring, insulin therapy, diet, and exercise.
Agnes affected are 14-18, 19-40, 41-60 you don't have to be a certain age to get it the source I got this this information from was http://www.mayoclinic.org