I’m a confused about my son’s laboratory test results. My five-year-old son was diagnosed with type 1 at 23 months old. He is Caucasian and is not overweight. At our last doctor’s appointment, the doctor ordered antibody tests to determine if he had a non-autoimmune form of diabetes that was recently discovered this past year. I did not think he had this form of diabetes because I think most kids with this form are diagnosed under a year. His father has celiac disease. So, an autoimmune disease is in the family.

Nevertheless, we did the test and now I’m confused with the results. His GAD-65 came out to 0.2 U/ml with ref range 1.0 or less, and his IA-2 result was less than 0.8 U/ml with ref range less than 0.8. They are normal. The doctor sent a letter stating that since the results were within normal range, it suggested that maybe my son had a non-autoimmune diabetes that would respond to sulfonylureas. He also wants my son to have a KCNJ11 mutational analysis.

With the holidays and the doctor here being so busy, I can’t seem to get answers. I don’t want to get my hopes up, but does it seem like it’s possible for my son to have a non-autoimmune form of diabetes? What will this new mutational analysis show?

There are two separate questions that you are asking. One, could your son have a non-autoimmune type of diabetes and, two, how to interpret antibody results and also the new genetic tests that look at very specific potassium channel defects “masquerading” as typical very young child-diabetes?

First question: any child who is diagnosed in the newborn period and probably until about two years of age could present with classical ketoacidosis and high glycemia, get treated with insulin and until recently never get re-diagnosed because the new tests were only just made available commercially. The benefit of making this diagnosis is that control of glucose is significantly easier with these pills than with insulin injections, A1c levels improve dramatically, daily glycemic excursions are reduced, and hypoglycemic reactions probably also lessened. Plus, quality of life is obviously improved when not needing multiple injections or insulin pumps.

The difficulty is that the antibody tests are not 100% foolproof and very young children often do not have positive antibodies even when tested at diagnosis. Years later, their antibody positivity status is even more problematic. So, positive antibodies would go against such a diagnosis, but negative antibodies won’t help. Islet cell antibodies and GAD-65 antibodies are usually the ones available for testing. Insulin antibodies themselves cannot be used once insulin has been injected, even with modern purified analogs. If the genetic tests are positive, and antibody levels negative, this would make one think seriously of trying with the oral agents rather than insulin.

Lastly, you are also correct that with other family members having autoimmune disorders, this increases the chances of “standard” type 1 autoimmune diabetes. But, since such autoimmune disorders are also not so rare, this, too, is not foolproof.

So, while there is no urgency, it is wise that your diabetes team is asking such questions and trying to determine if these new research findings are applicable to your child. So, please go back and discuss this in more detail with them so that you have a better understanding of the expensive and new tests.

SB