Maturity Onset Diabetes of the Young (MODY) refers to a group of autosomal dominant disorders, which present themselves generally in the second or third decades of life. MODYs are characterized by a reduction or loss in the capacity of the pancreas to release insulin. Six different forms of MODYs are recognized, of which MODY2 is the most common. Like all other MODYs, MODY2 is also characterized by non-ketotic hyperglycemia, presenting in young, non-obese individuals. In obese individuals, the age of onset may be further lowered. The hyperglycemia and the associated glucose intolerance, however, are of a mild nature, and the condition does not usually lead to long-term problems. Thus, microvascular complications, like nerve damages, kidney disease, and ocular complications are not as common as in other forms of diabetes.
MODY2 may be associated with pregnancy, in the form of gestational diabetes. Gestational diabetes needs to be controlled, in order to prevent complications to the fetus, including excess growth, low blood sugar, jaundice, and respiratory distress syndrome. Generally, MODY2 can be easily controlled by exercise and diet alone, without the need of any medications.
MODY2 is caused due to mutations in the Glucokinase (GCK) gene, located on chromosome 7. The glucokinase protein translated from this gene, serves as the glucose sensor for the beta cells of the pancreas. As soon as the glucose level in the blood rises over 90mg/dl, the glucokinase receptor recognizes it, and triggers insulin secretion. In mutated versions of the protein, this recognition is damaged, so that the glucokinase protein can only recognize serum glucose levels over 126-144mg/dl. The insulin trigger is, therefore, delayed, leading to the hyperglycemic condition.