I first heard of this about 6 months ago when we did all kinds of tests on our 4 year old whippet-x to find out why she was having accidents. We had ruled out UTI's, kidney infections, etc and the vet decided on a 2 week course of antibiotics. If that didn't work then her next step was going to be the test for this type of Diabetes. (We even monitored water intake for 2 weeks in case she was increased in her drinking habits etc).
I didn't research it as it seemed to sort itself out - so must have been a very low grade virus causing her to go more often and have less control. The vet said it was uncommon, but certainly treatable. If Chelsea HAD had it I wasn't overly worried, as she could be treated, and at least I would 'know' what the problem was.
I don't know that this helps you at all, but is just my most recent experience.
Wendy