My child was diagnosed with diabetes insipidus a little over a year ago. He had an abnormal brain MRI. So, he is seen by an endocrinologist, a pediatric neurosurgeon, a genetics doctor and, most recently, a neurologist. The neurologist is worried he may have DIDMOAD because it was discovered that his optic nerves measure only 2 mm bilaterally instead of 4 mm. We will be in the process of getting him tested. I would like to know how significant this finding is? He does not have all the symptoms, but is the diabetes insipidus in combination with the smaller than normal optic nerves enough to point to DIDMOAD? What kind of further testing should I expect?

DIDMOAD is a combination of diabetes insipidus (lack of hormones that control water balance via posterior pituitary), diabetes mellitus, optic atrophy and nerve deafness. There are some good research findings that can pinpoint the genetic abnormalities so ask your geneticist if these may be available to be measured. Detailed family history may also be important since DIDMOAD often can occur in other family members. It seems like you are getting excellent specialty care and that all of these specialists are consulting with each other for optimal recommendations. Being aware of the association with diabetes mellitus would require periodic glucose testing which you may want to discuss with the endocrinologist.

SB