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type 1. genetics

Discussion in 'Type 1 Diabetes' started by jinatki, Aug 4, 2016.

  1. jinatki

    jinatki Type 1 · Member

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    why do some people develop type 1 diabetes?
    i dont think the complete answer will be found in our genes!
    why?
    i was diagnosed with type 1 at age 15 & have lived with it for 33 years.
    now aged 48, i am 15 minutes younger than my identical twin sister, who is a nondiabetic!
    i would love to know if there are any other twin/s with type 1!?!
     
  2. tinyfilosofer

    tinyfilosofer Type 1 · Well-Known Member

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    It is a rather recessive gene and dad and mom must both be carrier and permutation means some kids will strike the lottery, but most kids will inherit at least one dominant gene which will suppress it totally. Siblings of t1 have 5% more chance of being t1 compared to regular people.
     
  3. tinyfilosofer

    tinyfilosofer Type 1 · Well-Known Member

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    But if you are identical, then it's the same genes. You need environment factor as well, eg virus, to trigger your immune system to attack your pancreas.
     
  4. catapillar

    catapillar Type 1 · Well-Known Member

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    There must be other twins with type 1 - I read that if one identical twin has type 1 the chance of the other twin getting it is about 50%. So there are sets of identical twins where both have it and about an equal amount of sets of identical twins like you and your sister, where only one lucky twin has it. So as well as the genetic predisposition, there must be some environmental factor to trigger. It's just it must be a very subtle combination of environmental things that cause the trigger, because I'm going to assume you and your sister grew up together so had a very similar environment. Maybe you caught a virus that she never did or something? Or maybe had a traumatic/stressful experience that she didn't.

    I'm afraid, because no one has identified the genes that put us at risk or the environmental things that can trigger type 1, the best you can put it down to at the moment is plain old bad luck.

    Edit: I found where I had read it - http://www.diabetes.org/diabetes-basics/genetics-of-diabetes.html
     
    #4 catapillar, Aug 4, 2016 at 5:35 AM
    Last edited by a moderator: Aug 4, 2016
  5. Jaylee

    Jaylee Type 1 · Expert
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    Hi,

    From what I know. Identical twins have a slight variation in the genome mapping..? Though they can look simalar. Along with "nature & nurture" elements.. It's not like "clones" in a controlled environment.

    In short. Different kinds of sh17 can happen to anyone...
     
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  6. MickyFinn

    MickyFinn Type 1 · Well-Known Member

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    Too little is known about the causes for most illnesses, not just diabetes. As Tinyfilosofa says, type 1 doesn't just require the recessive genetics, but also a trigger for it, and that's where the picture becomes less clear, other than in a lot of cases it being a virus that triggers a faulty immune response which attacks the pancreas.

    I also have Crohn's Disease, and no one fully knows all the causes of that either. Genetics are thought to play a huge part in it, in that if you have family history of it, you are far more likely to get it, although a TB like bacteria called MAP is thought to be one of the major causes. While it can run in families, however, I'm the first in my family to get that as well as type 1. There is simply not just one set of circumstances and that's what has made it so hard to build an entire picture of it.
     
  7. tim2000s

    tim2000s Type 1 · Expert
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    I had quite a long chat with one of the Exeter researchers about this topic. Whilst there is a very clear genetic link within families with Type 2, Type 1 has much less of one. From what I've read, genetically they can probably identify that within a lineage there is likely to be autoimmune disorder (and typically, if you look at families where there are T1s, you will find other autoimmune issues, as well as multiple autoimmune issues within a T1), but it's not obvious which of these will manifest or what might trigger it. Classic examples include Thyroid issues, Vitiligo, Psoriasis, some forms of arthritis, and of course T1 diabetes.

    As a result, it's much harder to trace a specific genetic lineage within T1.
     
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  8. azure

    azure Type 1 · Expert

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    @tim2000s Yes, that's what my consultant told me - 20% genes, 80% environmental.

    It's interesting that the 'Type 1 diabetes genes' aren't rare but most people who have them do not get Type 1.
     
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  9. rockape37

    rockape37 Type 1 · Well-Known Member

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    My dad is an identical twin and he is type 2 and he keeps his diabetes under good control.
    His twin brother is type1 but his control was terrible as a type 2 his control is still terrible.

    Regards

    Martin
     
  10. jinatki

    jinatki Type 1 · Member

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    As kids we did everything together & went everywhere together. When one of us went down with illness it was just a matter of time before the other followed. We both caught measles as babies & I can remember us having mumps at age 5 and missing out on the school trip to Bristol Zoo!
    When we about 15 I remember being sent home from school because I had developed a rash. I did not feel ill the school nurse said it could be German measles & therefore a risk to 2 pregnant teachers we had at that time.
    I remember this event most vividly because it was the first time in our lives that I fell ill but my sister did not.
    By the next day the rash had disappeared completely & after the weekend I was back in school.
    It was just before our 16th. birthday & I started losing weight dramatically. My eyesight was getting more & more blurry, I had thrush & nothing would clear it. I was so tired all the time I was falling asleep in school! All over my body my skin was dry & sore, especially on the palms of my hands.
    Then came the unquenchable thirst & constant visits to the loo.
    After a few days of this I knew I was not getting better but worse.
    I looked up my symptoms in the "Family Doctor" book (no internet in those days), that is when I knew I had Type 1 diabetes & would have to have to inject insulin for the rest of my life.
    The next day my sister & I left school for my doctors appointment. I was so weak & fatigued my sister carried me on her back all the way there, (about a mile).
    At the doctors my self_diagnosis was confirmed & my parents took me to hospital early the next day where I stayed for about 3 weeks, recovering & learning how to live with type 1 diabetes! xxx
     
  11. Robinredbreast

    Robinredbreast Type 1 · Oracle

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    Hi, I know of twins, a boy and a girl and the girl twin has type 1 ( she was diagnosed in her 20's, now 32 ).
     
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