As Fergus says, the word gets used as a sort of catch all .
It's not really an 'official term . It's most often used for :
LADA, latent autoimmune diabetes in adults. This is an autoimmune condition in which the beta cells are destroyed. It is at the moment classified as a subset of T1 diabetes but the B cells die off a bit more slowly than in classic T1. If it is diagnosed early enough there may be a period of a few years when the person isn't insulin dependent (80% need insulin by 5 years) Because it occurs in adulthood and doesn't have a fast onset It is often misdiagnosed as T2 *
.
http://www.diapedia.org/type-1-diabetes ... -the-adult
MODY. Maturity onset diabetes in the young. A misnamed type ; it is not T2 in the young, it was named when they didn't really know what it was. It can be diagnosed at any age . Like LADA it is often misdiagnosed as T2 when it is discovered in later life but it is also misdiagnosed as T1 when it appears in children and young people.
It is a disorder caused by the mutation of a gene so is inherited and 'runs' in families. ) The mutation results in a defect in the beta cells causing a reduction in insulin production or release.They have found several different mutations so we get MODY 1, MODY2 etc, I think they're up to 11 now. Some forms of MODY can be 'treated' with diet and exercise, some with oral medications and some with low doses of insulin.
They used to say that MODY was rare but now seem to be discovering more and more cases . The specialist unit in Exeter says it accounts for 1-2% of people with diabetes but some researchers think that it could be higher. In the UK one group of researchers suggested that 80% of MODY cases were misdiagnosed as either T1 or T 2.
http://www.diapedia.org/other-types-of- ... 51216/mody
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The insulin resistance that Elaine mentions is debated, (it may sometimes accompany but may not be characteristic, there are conflicting studies) A lot depends on definition . There is debate on the degree of autoimmune attack in people with low levels of antibodies. (there are non diabetics with low levels of GAD antibodies) There is a paper this month entitled LADA: Time for a New Definition where this issue is discussed.