Both my 24 year old son and 23 year old daughter were born with nesidioblastosis and had to have their pancreases removed when they were babies. What are the chances of my children’s children being born with the same problem?

I also would like to give encouragement to all the parents out there with children that have this problem. My children are now grown and doing very well with little or no complications other than having to take insulin. They just recently got insulin pumps and are doing great with them. They take no other medication and live as normal a life as anyone else their age. Don’t get discouraged, God gives special needs kids to special parents.

Nesidioblastosis or PHHI (Persistent Hyperinsulinemic Hypoglycemia of Infancy), as it is now called, is a rare condition occurring in approximately 1:50,000 births overall in Western Europe and North America. The commonest type seems to be an autosomal recessive abnormality of the sulfonylurea receptor gene (SUR-1) on the short arm of chromosome 11. Assuming that this is the form that both your children have, then the chance of their children being similarly affected would be quite small, about 1:500. However this figure is at best a generalisation because, in the last few years, there has developed a greatly increased understanding of both the clinical variations and the genetics of this problem.

To begin with, it is now recognised that there are two main types of islet cells pathology, one of which is focal and the other diffuse. Some have defects in the SUR-1 or Kir6.2 genes, but, in about half of the cases. no chromosomal defect has so far been detected, and there is another group also with defects in the same area. but where the inheritance seems to be dominant and which produces focal lesions. In yet another small group. the abnormality affects the specific enzymes glucokinase and glutamate dehydrogenase.

What this all means is that a more precise figure for the possibility of PHHI in your grandchildren will depend on a more exact understanding of the form the parents have. At this stage it may be difficult to arrive at this without some rather elaborate genetic testing. but it would certainly be a good idea at the appropriate time for your children to talk the whole matter over with a genetic counselor.

DOB