Family Prevalence of T1?

Does anyone else have a strong family prevalence of type 1? I have some strong genetic diabetes likelihood on my dad’s side. My dad is one of 7 kids. I have 20 first cousins. Out of 20, three of us have type 1. One child to each of 3 brothers.

I don’t know of any of our children having type 1 yet, and none of our parents had it. Our grandparents didn’t, and neither did their siblings. Not sure about great grands. I assume it came from a great-great grandmother who died young at the turn of the century. My photo of her shows her looking frail. But she didn’t go to the dr. Oklahoma wasn’t even a state yet.

Or is my family a statistical anomaly?

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There is definitely part of T1 that is genetic. I am the third generation in my family with T1. Still not everyone with a history of T1 will have T1. For instance none of my cousins (7) have T1. There is a mom with three sons who blogs and each of them have T1.

Estimates vary as to each person’s chance of having T1 given a direct lineage of T1. Last I read (others will correct me) each individual has about a 25% chance of having T1 if their parent has T1. This should not be confused by saying every 4th child will have T1. Rather it is each individual will have about a 25% chance.

Our two sons both in their 30’s do not have T1. So far the grandchildren do not either. Yet, it is conceivable that any of my descendants will have it. Just as being my mothers son meant I could have it. Likewise my mothers sister and she had T1 despite my mothers parents not having T1. Indeed each of my cousins children or their children’s children could have T1.

I am only T1 in large immediate family, and extended family (50+). Although several T2s diagnosed in 50s.

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Yes: my dad, my brother, my aunt/dad’s sister, my grandfather/dad’s father and possibly great grandmother (but she might’ve been type 2, I’m not sure). At least I was ready for it!

I think I’ve read several times that the risk of T1D is 3% in the general population and doubles if anyone in your immediate family has it, sibling or parent. Which would be 6%.

I’ve never seen the 25% stat, thought it was maybe 25-50% more likely? Either way, the 3 first cousins is a bit eye popping. :astonished:

Hi laceyna,
Yep, My Dad was type 1 LADA, His Dad was Type 1, not sure if he was LADA. My great Grandpa died young when the Veterinarian had trouble finding his appendix and he died on the kitchen table. So, for all we know He may have been LADA also. So yes it runs strong in my family. My Sister so far doesn’t present symptoms, so maybe she will not have it. Her Son also doesn’t have symptoms in his mid thirties. Both of my children are adopted, so they won’t inherit it from me but my son has type 2 in his biological background. Our knowledge of his background is very limited since we have not had any direct contact with his bio relatives.


There definitely is a genetic component to DM1. If a family member has it their close relatives are a higher risk for developing DM1.

I am an enigma. I do not have any family members w/ DM1 and was diagnosed in my early 30s

No one in my family has ever been diagnosed with type 1. My 30 yr old son does not have it so far.

From Joslin:

  • If an immediate relative (parent, brother, sister, son or daughter) has type 1 diabetes, one’s risk of developing type 1 diabetes is 10 to 20 times the risk of the general population; your risk can go from 1 in 100 to roughly 1 in 10 or possibly higher, depending on which family member has the diabetes and when they developed it.
  • If one child in a family has type 1 diabetes, their siblings have about a 1 in 10 risk of developing it by age 50.
  • The risk for a child of a parent with type 1 diabetes is lower if it is the mother — rather than the father — who has diabetes. “If the father has it, the risk is about 1 in 10 (10 percent) that his child will develop type 1 diabetes — the same as the risk to a sibling of an affected child,” Dr. Warram says. On the other hand, if the mother has type 1 diabetes and is age 25 or younger when the child is born, the risk is reduced to 1 in 25 (4 percent) and if the mother is over age 25, the risk drops to 1 in 100 — virtually the same as the average American.
  • If one of the parents developed type 1 diabetes before age 11, their child’s risk of developing type 1 diabetes is somewhat higher than these figures and lower if the parent was diagnosed after their 11th birthday.
  • About 1 in 7 people with type 1 has a condition known as type 2 polyglandular autoimmune syndrome. In addition to type 1 diabetes, these people have thyroid disease, malfunctioning adrenal glands and sometimes other immune disorders. For those with this syndrome, the child’s risk of having the syndrome, including type 1 diabetes, is 1 in 2, according to the American Diabetes Association (ADA).
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Can’t be sure in my family because on my father’s side we know that many of my aunt’s and uncles died as infants and toddlers but there wasn’t access to medical care where they lived so no diagnosis.

I have 10 siblings between my mom and dad and I’m the only one with diabetes. We are all adults and some are even middle aged. IMO this disease is truly the luck of the draw since technically all of my brothers and sisters have that 1 in 10 chance but I’m the only one who’s immune system went kamikaze.

My best friends mother had something like 4/7 kids with type 1 in her immediate sibling group. Thats the strangest thing I ever heard. They are genetically described as German-Prussian. I am the only one ever known to be in my family, but I am of Finnish ancestors (highest incidence of type 1 in the world), so I am sure there is a genetic component.

Six kids in my immediate family, and my dad was the oldest of six kids, so we have three aunts and two uncles, all of whom have their own families ranging in size from three to six kids, and many of those 1st cousins now have multi-child families of their own too. At a guess, something like 60 people in that sample. So far as I’ve been able to determine, only one other case of T1, my first cousin’s daughter. Other than that, no diabetes of any kind. So in my extended family at least, it seems to have been a total crapshoot.

Anyone else remember the thread on the old TuD site about this? I was trying to see if it was still in the archives somewhere. “Are you the lucky 1 (T1 that is)” – something like that. I think it was one of the first threads I posted on after lurking for a while…

I was one of 4 kids, and no one else 2 generations back or 2 generations forward has T1D (5 total generations).

Seems like I’m unique :stuck_out_tongue_closed_eyes:

For anyone who may be directly related to someone who has T1D, detecting it’s presence earlier is a large advantage to delay progression. is a non-profit that provides free anti-body blood testing for all first degree relatives of someone with T1D.

They test for five anti-bodies. If a person tests positive for two of those five, then they are diagnosed with stage 1 of T1D, an asymptomatic stage with normal blood sugar. This presents an opportunity to participate in medical studies designed to learn how to delay the disease progression and even inform efforts related to T1D prevention.

TrialNet operates over 200 centers world-wide. Although the organization is heavily weighted with a US presence, there are centers in Sweden, Australia, Germany, Italy, UK, Finland, and Canada.


I’m the only one with Type 1 diabetes in a fairly large extended family. However, my family does have a history of autoimmune conditions. My understanding is that it’s largely the risk of autoimmunity, rather than the specific autoimmune condition, that’s inherited.

I remember this one.
The chosen one.

(Wow, it was posted 10 years ago).

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I’ve been a member of TuD since 2007, and it’s incredible to think that that was 12 years ago now!

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“Chosen” one—that’s why I couldn’t find it! I knew it was around somewhere. Thanks!

ETA: and yes, one part of my memory was correct anyway: that was my first post on TuD, May 31, 2013, though I think I’d been a lurker for a bit before joining.

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My maternal grandmother and her 5 siblings all had adult onset diabetes, onset in their 40’s or 50’s. There are at least a few 2nd/3rd cousins with diabetes onset before 60 y.o. I’m T1 LADA and one daughter had T1 onset in childhood.

Is genetic disposition inherited from my GM’s family for T1 or T2? T2 had always be assumed, but T1 now seems much more likely.

I was the T1 trendsetter in my family, DX’d at 10 mos old in 1966.
Grandpa T2 on insulin in the 80’s
Brother T1 in his late 30’s in the late 90’s
Aunt T1 in her mid 40’s 2000-ish
Aunt in her 60’s T1 in 2010-ish.