Diabetes and genetics


#1

Hi :slight_smile:

I’m just curious if anyone is aware of their genetics when it comes to their diabetes? I took the 23andMe test a few months ago. Other than the ancestral DNA, which was very much what I expected and confirmed some educated guesses I had as well and a few minor surprises, it showed I had none of the diseases or was a carrier for anything they tested for except the double allele H63D for hereditary hemochromatosis. It’s a mutation with low penetrance, so I probably won’t have any problems with it.

I recently downloaded my raw genetic data from 23andMe and uploaded it to Promethease, which is a part of SNPedia [snipedia]. It’s a wiki for SNPs [snips] (single nucleotide polymorphisms). It yielded sooo many surprises, and was well worth the $12 it cost! :slight_smile: I have at least 10 different “snips” that I could find related to type 1 diabetes, that it’s not surprising I eventually developed it. My combined risk is at least 30x times that of the general population.
My family is also littered with autoimmune diseases in general, so I’m at an increased risk for other diseases as well, like 5x for Grave’s Disease (mom’s sister had it) and 6x for rheumatoid arthritis (mom’s sister, dad’s sister, my maternal grandfather’s mother) and plenty of other autoimmune disorders.

It intestingly also showed me that I have impaired enzymatic function for breaking down certain drugs, so I need lower doses than would be expected. It’s drugs like Warfarin, Ciclosporin, Amitriptyline (which I actually take as a migraine prophylactic). It also showed that I should stay away from Plavix, because it won’t help me as much and will significantly increase the risk of heart related “incidents”.


#2

I am the only type 1 (and the only diabetic) in my family that is known to have existed. However, I have Finnish, Swedish, and Danish heritage. Finland has the highest incidence of type 1 in the world, so I assume theres a link there. Sweden is the second highest. My friend from Saudi Arabia with type 1 also assumes some genetic influence because the Saudis have the third highest incidence in the world. He blames in-breeding.


#3

I haven’t done any genetic testing of the type you’re talking about, although I’m interested in doing it. I’m a research scientist in a biological field, so I’ve both professional and personal interests in population genetics and distributions.

What I do know is that I’m now the fourth person in four generations to develop LADA in my mother’s line: my great-grandmother had LADA (presumably, she was diagnosed in her late teens or early 20s); my grandmother had LADA (also presumably, she was diagnosed in her early 40s); my youngest brother was diagnosed with LADA in his early 20s; and I was diagnosed with LADA at 41. I also have a lot of people in my Mom’s family with Type 2 (a couple of uncles, my next-younger brother, etc.). So it’s quite possible these are all mixed together, we definitely have a lot of autoimmune disorders as well.

So yeah, although I don’t know for sure, it does seem likely that there are some genetic elements to whatever is going on in my family. My mom’s family is largely of Scottish (with a heavy dose of Scandinavian/Orkney & Faroe Islands influence), English, and Native American (Shawnee) descent.


#4

A theme that was extensively discussed a few years ago was the so-called ‘Viking Hypothesis,’ which held that the genetic predisposition to developing diabetes had been preserved during the last Ice Age as a survival advantage, at least in its milder forms, since having a higher level of glucose in the blood protects the body against frostbite. just as pine needles increase their sugar content to protect against freezing in the winter. The genetic group in which this genetic predisposition persisted were the Vikings, since they faced the coldest temperatures. Because the Viking lifestyle involved them travelling all over the place and settling in various regions throughout Europe, wherever they either were originally located, such as Denmark, or settled, such as Sicily, there are now high concentrations of diabetes.


#5

Seydiltz, is this related to the HLA b27 gene? I tested positive for that. Alas, in addition to just recently dx’s as 1.5 or LADA, I have crohn’s, ankylosing spondylitis, autoimmune liver disease and a few others. My mother had grave’s disease and my sister has RA. Weird thing is my younger siblings have no issues. However, they did not grow up in rual farming areas, as my sister with RA and I were both sprayed by a crop duster who didn’t close his chute while we were waiting for the bus as children. My hypothesis is that the while the genetic code was there, it needed an environmental trigger and me and sis got it in a big way.


#6

It is known that among twins there is a disconcordance for type 1 diabetes, so a genetic predisposition to develop the disease is not enough, but it also requires exposure to some environmental trigger. But there are probably so many different potential triggers or they are so ubiquitous, such as viruses or allergies, that they can’t be avoided.


#7

Well, this may be unscientific, but I certainly look like a Viking (2.0m, 85kg, and huge blonde/red beard) and have plenty of Scandinavian genetics on my mother’s side of the family :slight_smile: Seems plausible to me…

On the other side of the coin, however, is that such a hypothesis would make far more sense for Type 2 genetics, since Type 1 (even if accounting for how many develop as adults) dramatically decreases reproductive rates before the discovery of insulin. I mean, if you think about it, close to 100% of childhood cases of what we think of as Type 1 resulted in death before adulthood before insulin became available.


#8

I believe the Viking hypothesis holds that the diabetes gene, when it was positively selected during the last ice age 12,000 years ago, was sufficiently different from what it is now so that it would not have been as harmful as it now is.


#9

Hrmm, that is an interesting hypothesis. I’ll have to search for literature on that (unless you have some links at hand). That might, for example, shed some light on the difference between (my own type) of LADA T1 that is very slow-onset, and the more typical DKA-onset Type 1 in childhood or adulthood. The slow-onset of T1 could, presumably, provide some benefit in very cold climates if it didn’t result in immediate insulin-dependence.


#10

I suspect, too, that many Vikings had the gene for diabetes but did not go on to develop T1. Thus it could have been passed down the generations.


#11

Thats really interestin’, @Seydlitz . Thanks for the lead on that post. Never heard of that. I am also a big ‘bruiser’ of a blonde women. Luckily, I live in part of the US where there was a lot of settlement by the scandahoovians, so there are still plenty of men who will date me, LOL. Because I look Nordic, I am the butt of a lot of Viking jokes. Watch out for accusations of ‘Viking berserker syndrome’ if you ever visit Minnesota and happen to raise your voice, @David49 . I always thought being big is beneficial to our survival in cold climates, but its not that great for our cardiac health.

For my Saudi friend, does sugar do anything to keep you alive in the desert? Probably not because of the dehydration factor…

@Lemonz, Where are your peoples from? Did 23AndMe tell you? I know that test is more health condition oriented.


#12

Yeah, funnily enough, I’m also the only one in my family that I know of with type 1 diabetes, even though we apparently carry a high risk of type 1 diabetes.
I do have 67% Scandinavian DNA with highest matches for Norwegian and Danish ancestry. My 2nd highest is UK with 22%. All places, according to your list, with high incidences of type 1 diabetes (I even got it at at age 14).


#13

Interesting that you have Faroe Islands influence in you. I’m 100% Faroese as far back as I have traced my heritage. Lived there the first 19 years of my life, but moved to Denmark 9 years ago. :slight_smile:
My first doctor even asked which island my family hailed from. He said almost all his patients were from the same island which, incidentally, almost my entire family comes from as well. I blame the genetic isolation… lol :stuck_out_tongue:
23andMe said I had 600+ matches of relatives in the USA, so you think we are related as well? :smiley:


#14

My entire breakdown is 66.7% Scandinavian (with Norwegian and Danish matches), and 22.8% British and Irish (with UK match), 0.7% Iberian (makes sense as I’m Faroese, and we have had illegal Portugese traders there in the 17th and 18th centuries during the Danish Royal Trade Monopol), 0.6% French and German, 0.2% Ashkenazi Jewish (which was very surprising!) and finally 8.9% Broadly Northwestern European.

Even though I’m mostly Scandinavian, and a direct descendant of actual Vikings (the sailing and pillaging kind, and not only the farmers :stuck_out_tongue: ), I don’t really look Scandinavian. I have some features typical of Scandinavians, such as being pretty tall (189 cm or 6’2"), straight hair and light skin, but I also have dark brown hair and so brown eyes you almost can’t see my pupils. :stuck_out_tongue:


#15

I’m a direct descendant of Vikings, and my genetic testing also showed that I have genes that give me a predisposition for higher fasting BG, but I only have a slightly elevated risk of type 2.

That would make sense, because I developed my type 1 very rapidly with DKA at age 14. No time for me to reproduce. :slight_smile: I was at my doctor in January of 2004 because I kept getting headaches, all blood tests were normal except some liver stuff was slightly elevated. I retook the blood tests and then everything was normal. Then in May I almost went into a diabetic coma, and spent 10 days in the hospital.


#16

Hah, it’s possible! My grandmother’s people were apparently all over the islands to the north of Scotland. Orkney, Shetland, and Faroe Islands, and then somehow they ended up in the U.S. Mostly illiterate on that side up until my parent’s generation, so we don’t know much about who they were or where in particular they were from. Wherever they came from they brought diabetes with them, apparently!


#17

Jenn, Do you mind me asking what were your symptoms with Crohn’s and how did they diagnose you with it. Feel free to message me on he side. :slight_smile: I am being tested for that again. I was years ago too but they said I was negative. Last year I found out that I have the HLA-B27 gene They tested me since I was having a ton of arthritis issues but no RA factor. They were thinking possible AS last year but now I’m not sure. I am just under the Seronegative Spondylarthropthy category. I have had Type 1 Diabetes for almost 25 years. Plus have some family members with other autoimmune diseases.
Thanks.


#18

That’s interesting. I haven’t yet but am wanting too. There are just so many types and I’m not sure what the best type are.


#19

Have they done any x-rays of your joints? Have they considered psoriatic arthritis? I’ve had it for about 20 years, along with psoriasis (for about 30 years). I’ve been on autoimmune suppressants (biologics and dmards) for about 20 years.

Here’s a link which may shed some light.

edited to correct spelling error and clarity of time.


#20

Although type 1 diabetes usually appears no sooner than puberty, I suspect that during the many ages of human existence prior to our present highly developed social rules regarding sexual behavior, even those who were too young to be married by our standards would still be reproducing and sustaining the diabetes genes.