A New MODY Gene Identified

A team at Joslin has been looking for more MODY genes and has found one they say should be added to the six currently tested for. This gene is named BLK. One of its many functions is to trigger insulin production.

The discovery is reported here:

Mutations at the BLK locus linked to maturity onset diabetes of the young and β-cell dysfunction. Maciej Borowie et al. PNAS, Published online before print August 10, 2009, doi: 10.1073/pnas.0906474106

You can read a slightly more informative report on this study here:

Joslin Study Identifies Gene Linked To Rare Form Of Diabetes

MODY is believed to cause 2% to 3% of all cases of diabetes. As reported there are currently eight genes known to cause MODY, but these account for only 85% of those whose family histories are suggestive. Joslin's researchers are looking for the genes that cause the other 15%.

I had volunteered for this study but was unable to participate because one requirement is that participants have a fairly large number of relatives with diabetes. My extended family was too small to qualify.

Unfortunately, when I contacted them two years ago, the Joslin researchers were not willing to share findings with the study subjects. So whatever the benefits of this study for science, it won't help those of you with clear-cut MODY family histories who don't test for the known genes.

For those of you who aren't familiar with MODY, you can find a detailed description of what it is here: MODY: It's Not Type 1 or Type 2 but Something Else.

Because I maintain this MODY page I get a lot of mail from people diagnosed with Type 2 Diabetes who are not fat who are wondering if they have MODY. Most of them do not. Slow onset autoimmune diabetes (LADA) is much more common than MODY and is a much more likely cause for high blood sugars in normal weight people in their 30s and older.

One key thing to understand about MODY is that if you have it, you will have had abnormal blood sugars all your life in some form or other. Blood sugar problems that emerge suddenly and deteriorate over a year or two are much more likely to be autoimmune in nature. The blood sugars associated with MODY tend to stay relatively stable.

So if you are a thin or normal weight person diagnosed with Type 2 diabetes, don't even consider MODY as a possible cause for your diabetes unless you have had a full set of Type 1 antibody tests that are negative, a normal fasting C-peptide test (several forms of MODY only affect insulin secretion in response to meals), have no history of any other autoimmune disease, and have a life long history suggestive of abnormal glucose tolerance.

Unfortunately, as you can see from the reporting of this story in Medical News Today, the only reason scientists are working on MODY is because they hope to find genes implicated in Type 2 diabetes. Once they find a new gene that affects insulin secretion they are done. This means that once you are diagnosed with MODY by a gene test you rarely will be able to find out anything further about the probable course of the kind of MODY you have or even about the best treatments.

This is because all the money in diabetes is in treating the millions with Type 2 and the funding goes into studies that could turn into blockbuster drugs for Type 2.

Meanwhile we people with MODY have to muddle along on our own, often without the help of doctors who have any knowledge of what MODY is.

One thing I would like to make clear before I leave this discussion is this: It is not true that "MODY is simpler to diagnose and treat than the other forms of diabetes," as stated in the Medical News Today article. In fact, most of us with MODY go through years of misdiagnosis and inappropriate treatment.

Each genetic form of MODY is different, and they each require different treatment approaches. Finding the one that works for your own specific case can take a lot of work and because prescription drugs are involved you will need the support of an endocrinologist willing to work with you.

Since many endos have zero knowledge about MODY, many people with MODY get the same miserably poor treatment as the rest of the Type 2 community, and end up with the 8%+ A1cs that guarantee they will develop complications.

Because contrary to what you may read online, every form of MODY causes complications, it is only a matter of which one. MODY-2 (GCK) doesn't cause neuropathy or retinopathy, just fatal heart attacks, often striking the young. The HNF MODYs cause blood sugars high enough to produce all the classic -pathies and the sulfonylurea drugs often prescribed for them do not give the normal blood sugars that will prevent these complications. Only meal-time insulin can do this though some people with MODY-3 respond very well to Byetta. The gene responsible for MODY-3 can also cause congenital kidney malformations that lead to an early death if not diagnosed correctly.

So if you are diagnosed with MODY in any form, you will have to fight very hard to get appropriate treatment. If you just rely on your doctor and believe that MODY is "easy to treat" and that A1cs near 7% are all you need to attain, you are deluding yourself.

I have written to the researchers who identified this latest MODY gene to see if I can find out anything more about BLK MODY, but my guess is that having found the gene they will move on and those who have the gene will be left in the dark as to what it means and how to best treat it.