The hallmark features of the disease are high blood sugar levels resulting from a shortage of the hormone insulin, which resembles diabetes mellitus. Diabetes mellitus is typically the first symptom of WS, usually it is diagnosed at age 6. Nearly everyone who has WS and has developed diabetes mellitus has to undergo insulin replacement therapy.
Most of those affected with WS develop insulin-dependent diabetes mellitus before the age of 16, (about 87% of patients do). The Carbohydrates that humans consume are normally processed by the digestive system into glucose that later circulates into the blood as an energy source for bodily functions. A hormone produced by the Pancreas, (insulin), allows muscle and fat cells to take up glucose. In diabetes mellitus, the pancreas doesn’t produce enough insulin which results in the cells not being able to take up enough glucose and the patients blood sugar gets too high. As a result, the patient will need daily injections of insulin to control the blood sugar. Further symptoms of diabetes mellitus include frequent urination, excessive thirst, increased appetite, weight loss, and blurred vision.