Should You Be Tested for MODY?

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Diabetes is sometimes misdiagnosed. For example, people are often told they have Type 1 or Type 2, when they actually have MODY, also called maturity-onset diabetes of the young or monogenic diabetes. Might you be one of these people? And should you care?

A company called Athena Diagnostics thinks you might benefit from knowing your real diagnosis. At the American Association of Diabetes Educators conference last week, one of their experts shared some good information with me. So I did some more research on my own.

What is MODY?
MODY is a group of at least six genetic defects that damage insulin response. Each type of defect has different symptoms and may benefit from different therapies. Some cause severe high blood sugar levels; others damage the kidneys more; still another can wipe out a person’s whole pancreas, not just the beta cells. On the therapy side, some can be managed with lifestyle, some benefit from sulfonylureas, and others need insulin.

It is estimated that as many as 5% of all diabetes cases are MODY. People of Asian Indian descent may have more MODY. In a UK study, MODY was nearly as common as Type 2 among white youth.

Unlike Types 1 and 2, which are caused by multiple genetic and environmental factors, MODY is the result of a defect in a single dominant gene. So you have a 50% chance of passing it to children. Probably, environment and behavior don’t have much to do with it.

Signs Your Diabetes Might Be MODY
According to the brochures I was given, a person diagnosed with Type 1 might have MODY if they:

  • Were diagnosed before 6 months of age
  • Have a family history of a parent having diabetes (only 2% to 4% of people with Type 1 have an affected parent)
  • Have detectable insulin production three years or more after diagnosis
  • Have no immune antibodies to their islet cells, especially at diagnosis

A person diagnosed with Type 2 might have MODY if they:

  • Are not markedly heavy or sedentary
  • Never had acanthosis nigricans: a dark, velvety discoloration in skin folds and creases, such as in the neck, armpits, and groin
  • Have no evidence of insulin resistance, with fasting C-peptide levels (a marker of insulin production) within the normal range

Why Would You Be Tested?
Since MODY is 50% likely to be passed down to a person’s children, it would be worth knowing if you had it before having children of your own. Also, knowing you have MODY might allow you and your health-care team to provide more appropriate medical treatment.

I especially worry about the people with Type 2 who actually have MODY or LADA (latent autoimmune diabetes of adults). Many of them may have been denied insulin that would have saved their lives or made them better. However, people with Type 2 are often being prescribed insulin earlier now, so maybe that isn’t as much of a problem.

Those with MODY misdiagnosed as having Type 1 might be able to switch from insulin to a sulfonylurea in some cases. It would depend on which type of MODY they have, which requires genetic testing to find out.

This genetic testing is what Athena Diagnostics (my chief informants) sell, so you have to take that into account. The whole panel of tests could run you about $3500. Your medical insurance might pay for the tests, but some plans have genetic testing exclusions, meaning they might not pay for the MODY tests. If you can show that the testing would affect your treatment, they might have to cover it.

My own take is that, if your doctors are treating you well, based on your personal symptoms, history, and numbers, you might not need to know if you have MODY. If they are treating you as a diagnosis, according to a generic formula, then you would benefit from finding out. If you are a so-called “thin Type 2,” you might clear up some confusion by testing. And if you are thinking of starting a family, testing would be a very good idea.

I learned lots more at the AADE conference. I’ll be reporting in the coming weeks on driving, blood glucose awareness, mindful eating, and interesting new ways to change behaviors. My own talk on sex and diabetes went quite well, I thought. I’ll have to see the participant evaluations to be sure.

I really don’t like Las Vegas. The strip was like one gigantic shopping mall on top of one gigantic casino. Loud music playing everywhere. But I think I was in a minority — most people I saw seemed to be having a good time. Maybe someone can explain it to me.

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