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March 31, 2000

Diagnosis and Symptoms

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Question from Yellowknife, Northwest Territories, Canada:

I’d like to know more about Type�1B, MODY, and the various mitochondrial types of diabetes that have been mentioned in other answers. My six year old Caucasian daughter has not required insulin since 4 days after being diagnosed with type 1 a year ago. Autoantibody tests were negative, as was a C-peptide test. We’ve been considering using small doses of Ultralente to try to extend her honeymoon, but I’m wondering if that would be appropriate if this might be something other than Type�1A.

Answer:

From: DTeam Staff

Your daughter’s story is an unusual one specially on account of the very short period of insulin dependence. It is first of all just possible that she does not have diabetes at all because blood sugar can be raised as part of an acute response to stress, including the stress a little girl might feel on suddenly being exposed to a hospital environment. However I am sure this possibility was considered.

Whilst the commonest form of diabetes in a Caucasian six year old is autoimmune Type 1A, I think that you should ask the doctor for more details about the negative antibody test. If this was for the usual three antibodies and all were negative that would be conclusive evidence against Type 1A. If only one antibody was tested for, which sometimes happens, then it is still possible that the others might be positive and it would be worth repeating the test in order to be convinced that the problem was not a very early instance of type 1A diabetes.

Assuming though that the glucose intolerance was real and that the antibody titres were all normal then the next diagnosis to consider is Type 1B Diabetes. This presents exactly as does Type 1A acutely and with insulin dependance, the antibody tests are normal and in about 50% of cases the need for insulin can be dispensed with after a short period, though not usually as short as four days. Type 1B constitutes only about 5% of new onset cases amongst Caucasian children but makes up over 50% in Hispanic and African American children. Some of these cases are linked with specific chromosomal changes; but for the most part the condition is not understood in molecular terms.

There are at least five different specific forms of MODY and each can have variants. They reflect specific enzyme defects of which the commonest is one called hexokinase. In the last few years it has also been increasingly recognised that the typical adult form of Type 2 diabetes can present in young children characterised by a strong family history, increased stature and insulin resistance. This has been especially noted in peoples like the Pima Indians and in circumpolar populations where there have been a changes from a traditional diet to a more western one; but the increasing incidence has also been noted in the developed world.

Last on your list are the mitochondrial forms of diabetes which in that they interfere with basic energy supply are nearly always associated with other problems like deafness, diabetes insipidus, optic atrophy, lactic acidosis and severe muscular weakness.

To cut a long story short, I think your daughter is a rather mild example of Type 1B diabetes. I would be inclined not to give her insulin as long as her Hemoglobin A1c test stays within normal limits; but to emphasise an appropriate body weight for her height and lots of exercise compatible with your winter climate. If her doctor really feels that something more is required the oral drug metformin might be first considered and finally if insulin should be restarted there is a new one called glargine which can be given once daily and provides for a very even release; but I am not sure that it is yet available in Canada.

DOB