Low blood sugars are known to cause brain damage in newborn babies. One of the most common causes of low blood sugars persisting beyond the new born period is a condition called congenital hyperinsulinism (HI). This is a disease whereby the pancreas secretes too much insulin and causes low blood sugars. Twenty to forty percent of these babies will have brain damage. There are two forms of this disease. In one form only a small part of the pancreas makes too much insulin (focal HI) and in the other, the whole pancreas make too much insulin (diffuse HI). If a surgeon could know which part of the pancreas has the focal lesion he could remove it and cure the patient.