What condition is characterized by a deficiency of insulin leading to high blood glucose levels?

The condition characterized by a deficiency of insulin leading to high blood glucose levels is diabetes. In diabetes, the body's ability to produce or respond to insulin is impaired, resulting in elevated glucose levels in the bloodstream. This is a significant concern as it can lead to various short- and long-term health complications.

Hyperglycemia, while it describes the state of elevated blood glucose levels, does not specify the underlying cause, such as the lack of insulin. Hypoglycemia refers to low blood glucose levels, which is the opposite condition. Gestational diabetes specifically occurs during pregnancy and is characterized by high blood glucose levels but is not a permanent condition inherent in all individuals with diabetes. Thus, diabetes is the correct choice in this context, as it encompasses the chronic condition of insulin deficiency leading to hyperglycemia.