My eight year old daughter has Autoimmune Polyglandular Syndrome Type II and also has significant neurological involvement (mental retardation, seizures), and I am wondering if her GAD antibody results were high enough to cause neurological impairment as well as impending diabetes. She is presently undiagnosed for a unifying syndrome, and her GAD was positive at 0.67. Much of the literature uses different scales so this is difficult to interpret. Is my daughter’s GAD antibody level mild, moderate, or high?

In our laboratory, an anti-GAD65 index of greater than 0.05 would be considered positive, and one greater than 0.5 would be considered as high (extremely high is not defined). Perhaps you should talk to the laboratory that did the test as there is some variation both in results and the way they are expressed. In any case though, all the evidence to date indicates that autoantibodies reflect tissue damage rather than causing it.

I don’t know that I can offer much help on the issue of a ‘unifying syndrome’ especially as you don’t tell us which components of Autoimmune Polyglandular Syndrome Type II your daughter has and at what age the diagnosis was made. It is quite possible of course that the mental retardation and the seizures are not connected with the autoimmunity. It is also possible though, that at some stage she had undiagnosed hypothyroidism which is the most common companion to diabetes in this syndrome which might explain the developmental delay.

It is also possible that at an early age there were repeated episodes of hypoglycemia which can occur in the preclinical phase of the diabetes because of delayed first phase insulin release from the damaged islet cells. This could explain both the developmental problem and the seizures. There are some other very rare possibilities.

DOB