Type 1 diabetes!

You might be interested in Dr. Gabor Mate, who wrote a fascinating book which lays out his theories about the sometimes-serious physiological changes which can result from long-term exposure to the stress of emotional repression. It's called When The Body Says No, and it's beautifully and compassionately written. It's my third favorite book (after The Divided Mind and Hope & Help For Your Nerves), and although I don't remember whether he mentions diabetes, once you believe in the power of our brains to affect our physiology, you might develop your own answer.

That being said, if you are looking for an answer that says "oh sure, diabetes (type whatever) is TMS and therefore you can apply TMS techniques and be cured" that may be asking too much. Some physiological changes are reversible, but others may not be. And doesn't Type 1 have a genetic component? But I guess that also depends upon your belief in the power of self-healing.

Still, all THAT being said - I think that any injury, illness, or condition can be mitigated with mindbody techniques. Just as stress is well-known (and accepted by the traditional medical community) to make many conditions worse.