MODY isn’t a form of Type 2, because people who have the commoner forms are NOT insulin resistant. The classical definition of Type 2 includes insulin resistance. My insulin/carb ratio is between 1/12 and 1/15. A type 2 of my age and size might have one of 1/5. And I can’t use more than 3 units of basal. A Type 2 of my size might use 30 or more!
However, a lot of people with MODY are misdiagnosed with Type 2 and since they aren’t put on insulin no one discovers they are insulin sensitive! People with MODY respond very strongly to the sulfonylurea drugs that used to be given to all people with Type 2 and now are only given to some.
Also, MODY used to be diagnosed mainly in kids only because only the very worst cases got diagnosed, but I’ve met a few people diagnosed in their 30s (with gene tests) after a GD pregnancy. I should have been diagnosed then had it not been 22 years ago when such things were unknown. It isn’t usual for a 117 pound woman to develop GD a few weeks into a pregnancy and nowadays that would trigger some further testing!
The commoner forms of MODY involve gene defects that cause failure to secrete insulin as blood sugars rise, so for many people fasting bgs stay near normal and they can’t get diagnosed until quite old when they’ve burnt out the beta cells and are mistaken for Type 2s. There is another common form of MODY where the blood sugars are always mildly elevated and cannot be lowered even with insulin but these people don’t get complications.
Also, with the more common form of MODY there may be a very low renal threshold and they spill urine at 140 mg/dl! Some have other kidney irregularities. I personally have an extremely HIGH renal threshold, which is another reason I had so much trouble getting diagnosed. I don’t spill detectable glucose into urine until I go over 250 mg/dl!
I hear from so many non-obese people who have oddball forms of non-insulin resistant diabetes thanks to the MODY page on my site, that I’m starting to think there are a LOT more forms of diabetes out there than anyone realizes.
When there were no real treatments, it didn’t matter. As new treatments come available which respond to specific causes of diabetes it does.
For example, some people with fairly severe forms of the more common form of MODY appear to do extremely well on Byetta and I personally had a dramatic response to Januvia, though I stopped taking it due to it’s possible ability to promote melanoma.