MPN Voice
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Jak2+ up your risk?

I am on a face book site which believe me sometimes can be scary. But a couple people on there keep saying that having the Jak2+ gene makes your stroke risk higher, much higher and your platelets run lower so you can have strokes at lower numbers. Scary to say the least! Has anyone heard this? The MPN expert I saw or my local said nothing about if your Jak2+ your risk is higher and if you negative or Calr you have a much lower risk. This is for ET. My local Dr said he would be happy if mine stayed in the 500's.

Maz can you ask your expert if this is something new? Very worrisome to say the least because most of us are Jak2+. Thanks all, Mickey

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Not an expert myself, and sure Maz will be able to provide more information, but to me this seems scaremongering. Maybe its just a statistical thing that more people with PV are Jak2 Positive (95%) i dont know.

My understanding is the risk of stroke increases in uncontrolled ET/PV, i.e for people who have not yet been diagnosed, the people I have spoken to who have had strokes seem to have had them pre diagnosis.

If your MPN expert hasnt expressed any concern to you at being an increased stroke risk, I would expect he/she would know better than what may well be chinese whispers on an online forum.

If you have concerns i would have a chat with your MPN expert more than your GP just because they are better placed to give advice.

I do agree with you though that when you read things online it can cause concern, believe me when i was originally diagnosed i was convinced at first i would be dead within 3 years - the internet is great at times, but maybe not always factually correct.

All the best - hope you can get the information you need to put your mind at rest.



Thanks Paul, I agree, neither my MPN expert or my local Hemo Dr express concerned over the Jak2+, just it adds up to having an MPN as ET is a diagnosis of exclusion they say. I'm sure the one who is saying it and believe me she says it to everyone, LOL. She is frustrated as we all were with medicine and this disease at least I'm trying to rationalized it. But she keeps telling everyone if your Jak2+ there risk is greater of a clot/stroke and they have lower numbers when they are at risk. (she says she was in the 500's when she had clots everywhere). My local Hemo Dr said he would happy if mine were in the 500's and my MPN expert said do not worry until it reaches a million, actually he said 1.5 million then he said there is more a risk of a bleed.

It is scaremongering it scares people, I'm almost convinced one morning I will not wake up and I need to get that out of my head. Every twinge, hot flash, headache I think I'm doomed. Before ET or should I say diag of ET because my platelets were high for a year before I even (I was the one who question it) questioned it a wellness test for work.

Thanks again! I love this forum! :)


What is the link to the. Fb site . I'll be interested in reading this. I have et jak positive too. I think if platelets low 400 or less .lowers risk of strokes.


My experience of FB sites is not really all that positive. You can pick up some links to useful articles on the sites but they seem to me to suffer from a deal of in-fighting that you never see here. Some things you read on there are just plain untrue and you sometimes need to do a lot more research to separate the truth out. This is easier if you have been around MPNs for more than 20years as I have but I imagine it can be quite scary for newcomers. I think there appears to be some correlation between gene mutations and risk but I expect Maz will give the best answer to your query



You know Mickey, the very reason I don't go reading all those comments made by non experts in the field is because for 99.9% of the time the information you read is just plain wrong.

Can I make a suggestion that I make to all the new people I buddy? (With the greatest of respect because I know quite a number of folk spend a lot of time on this site)

Try to avoid other people's worries and problems unless you feel you can be a positive help without worrying yourself.

This is a wonderful site ( personally I don't go on Facebook either, life's too short as far as I'm concerned) but you do read about a lot of worrying things that most likely will NEVER EVER apply to you.

Try to look outwards 100% of the time, give thanks for what you do have even if it's simply sitting and enjoying the garden, or a beautiful walk, or delicious lunch, and treat your PV as a mere nuisance which isn't going to jolly well make you worry and feel down.

There was a wonderful interview on patient power last week by a haematologist who said many of his colleagues now tend to go by how the patient FEELS just as much as what his readings are.

I wouldn't worry about JAK 2 or even look at that silly person ranting on Facebook again.

None of us need stress in our lives and the more you worry the more stressed you will become.




You guys are so wonderful, this is where I come when I need support and advice! I sooo wish I live in the UK! What a wonderful group this is! You always make me feel better! I do not need to be stressed out for sure, I'm stressed enough, LOL.


I can shed some light here.... I am Jak+ and I stroked with platlets of only 453. I had this conversation with the top experts in NY. The issue is the mix of your blood that causes strokes...not just one thing like platlets or mutation status. There is "some data" but "no proven definitive correlation" that jak2+= higher risk. In fact, the top researchers are not exactly sure what the jak2 means is way more complex than saying X causes Y. They think the disease driver is possibly something else thatbisbhigher up the "mutation cascade". So, in end of the day- you can't change your mutational status and you can't live life in fear- so do what you can to lower risk and carry on. I hope that helps at least a little....

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Yes it does thank you so very much! I heard one of the experts say you can go out on the street and test everyone walking up and down the street and some will have the Jak2 mutation with no MPN and where all their numbers are normal. I think it was an article where it was a very small number of people and like my GP says if you have 10 people and 2 have a stroke then the numbers are high, if you have 2000 people and 2 have a stroke it would not even be mentioned.

My expert who I saw in December runs the MPN clinic at John Hopkins and does tons of research I heard in his spare time no less, actually told me to stop worrying, he said so you have high platelets (of course he looked at everything else) he said people with low platelets and normal platelets have strokes. In the US some of the experts are now being very cautious to medicine and age. Before it was your over 60 thats the magic age, now you are hearing more and more of looking at the platelet count and of course everything else and not just going by age. Wish all the experts would get together and agree on the samething. :). Would make our lives a little easier. Thank you! all the support and information I get from this site has kept me going!


Sounds like you have a well informed doc! Good luck to you.


I left the Facebook group about 12 months ago due to infighting and horror stories. I never found any useful information on there ~ so it was no loss.

I had a small stroke before PV diagnosis. In fact it was what led the Doctors to the diagnosis of PV. I'm Jak 2 positive but my platelets are always low (or normal)

I'm treated with Aspirin (daily) and venesection when needed. I rarely even think about the fact that I could have another stroke. I trust that my Hemo and GP are working to keep me healthy and I'm a firm believer in knowledge being the key to keeping in good health.

I keep myself hydrated, eat healthily and avoid unnecessary stress. Yes, I could have another stroke, but I'm now in a position where that's less likely to happen, because I have wonderful Doctors looking out for me.

One of my favourite quotes is “I've had a lot of worries in my life, most of which never happened.” ― Mark Twain

Keep positive and happy. Karina x


Thank you soooo much Karina, somedays I just sit and cry when I read all those posts on that facebook site. I'm between my MPN expert and my local Dr who I like but all he talks about is HU, dismisses all side effects and any other medicine and I'm not sure he takes much an interest in this. The MPN expert was very reassuring. The facebook site is saying take the HU you will stroke out even at low levels, you will get TIA's or Strokes especially if you are Jak2+ your risk is very high! oh my gosh talk about scaring me to death. So my local says take HU, the MPN expert says do not take it, but all the others say HU is first line, My MPN expert is from Hopkins he runs a clinic for MPN's and that is his field of study. oh my gosh well I would like to try to interferon 2A pegasys but to get back to the expert I have to wait until May. UGH. Thank you this site always makes me feel better!

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Hello Mickey, reply from Prof Harrison - The whole picture needs to be taken into account for assessment of the individual patient. At the moment these differences are apparent (sometimes) when we look at a few hundred patients...

What you must bear in mind when you are reading information on any group is that it is the view of that person writing the information, and that they have been told that by their doctor, it does not necessarily mean it applies to us all, and also the sites may not always be being checked by a medical professional.



Such a good response! I so appreciate you asking Maz, thank you so very much and Thank Prof Harrison for me. She is absolutely right the remarks came from two individuals and neither one will say where they got that information from and the site is not checked by any medical professionals. I love this forum, Thanks again Mickey!

I'm just sorry I don't reside where you guys are, this forum has such wonderful people!


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