Jak 2+ or Jak 2-

[mickey64]

Questions to all, does anyone know what the difference is if you are Jak 2 positive verses Jak 2 negative?? I read somewhere where everyone has the Jak 2 gene. So if your Jak 2 positive your diag is 100% for sure and if its negative? how can they make the same diag? Just mind boggling to say the least. Anyone have any clues. Thanks

[Cdseiter]

I'll try to explain and bit confuse you further. Yes, everyone has the JAK2 gene. The test does not refer to presence of the gene but rather whether or not the gene has spintaneously mutated. If a person is JAK2+, they are positive for the mutation meaning they have a mutated gene. If you have a mutated gene - you have an MPN and it is only a question of which one.

If a person is negative or lacks the jak2 mutation, it is still possible for them to have an MPN. There are other mutations like exon 12 , exon 13 and calr that they test for if there are clinical signs of the disease. ...

[Cdseiter in reply to Cdseiter]

The jak2 gene is considered a signaling pathway - in essence, it is the switch that turns on the overproduction of cells. That is why it is so important.

Although docs have figured out how to turn the switch off with jak2 inhibitors, they are not sure what else gets turned off when one flips off the jak2 switch. So it is cutting edge stuff.

[blulou in reply to Cdseiter]

Question the word spontaneous. Benzene and radiation are two possible causes of the mutation.

[mickey64 in reply to blulou]

I believe it, I had tons of x-rays, ct scans and pet scans over the last three years. I was showing my husband the disc from all of them and it must have been 20. Then my husband has one xray and I suggested he got a CT scan and his Dr oh my gosh no way do you how much radiation in one CT scan!!!!. I really truly believe radiation is a big cause of this.

[mickey64 in reply to Cdseiter]

Thanks yes they did test for all those I am negative for all the others. I do have a question which I know sound silly but on my test it had a value of 10.3 does anyone know what that means??? there was no range just that value 10.3 and positive for the jak 2+. I find it odd when they did my BMB they did not do a second test for the jak2+ does anyone else find that odd???

[Cdseiter in reply to mickey64]

Im just guessjng, but it might be a quantitative JAK2 test....which would mean your allele burden (or percentage mutated) is 10.3%.

[tracey13]

Seems to be the jak 2 positive gene is more active than the negative gene.

My husband has the positive and is having monthly venesections.

He's just started hydroxocarbide on Friday so fingers crossed it slows the bone marrow down.

Tracey

[mickey64 in reply to tracey13]

I'm not so sure about that because some people that have Jak 2 negative have just as high platelet counts. Who knows but it is interesting, I also saw where on my blood work it said 10.3 value or range but there is nothing to compare it to, I find it odd when he did the bone marrow that he checked for everything else which was negative but did not check for that? but no one can explain what that means. LOL

[Mazcd Partner MPNVoice]

Hi Mickey, this might help to explain it mpdvoice.org.uk/research/th... regards, Maz

[mickey64 in reply to Mazcd]

Thanks Maz, as always you are very very helpful!

[StanM in reply to Mazcd]

Thanks for this useful information

[idi75 in reply to Mazcd]

Thanks Maz, very helpful information.

My high hgb. was picked up at a routine blood test and I was referred to a good consultant haematologist. I was jak2 negative and also negative for the other mutations now recognised in MPN's. I had no other symptoms such as enlarged spleen; no other counts were out of norm. There was no evidence to support secondary causes, my consultant concluded that I had 'Polycythaemia - undermined cause' and it was very unlikely that I had a true MPN. I needed venesections every 3 - 4 months to keep my PCV (Hct.) below 0.45. Once this was achieved the rise in my PCV slowed and I have not needed a venesection since beginning of March this year. However I do have 3 types of slightly 'out of norm' immature blood cells and these have increased at each blood test, I think this may be a sign of anaemia. I have another routine blood test next week but my haem. doesn't seem to be concerned at the moment. So to anyone diagnosed with high PCV but jak2 negative don't assume the worst, diagnosis of MPNs has made great strides but it is still not definitive.

Hope this helps.

[MFBMT2011 in reply to Mazcd]

Maz that link comes up as a 404 error for me. Which part of mpdvoice is it referring to?

[Mazcd Partner MPNVoice in reply to MFBMT2011]

Hi this post is over a year old the link is to our old website you now need

mpnvoice.org.uk/about-mpns/...

[MFBMT2011 in reply to Mazcd]

Thanks. Doing some Jak2 basic research for an Aussie buddy and ended up here!

Chris

[MarkD6701]

I was diagnosed with JAK2 positive in January although they can't quite work out which MPN I have as it can be difficult to work out, even under a microscope - apparently.

I read recently that they are thinking of reclassifying MPNs just as either JAK2 positive or JAK2 negative and removing ET, PV etc.

[Aime]

Hi, I have Pv and am jak2 negative which is apparently quite unusual, trust me! As someone else has said it probably means that some of the other genes, which I was told were too expensive to test for have mutated. Not sure if one is more active than the other, being negative certainly did not mean my PV was inactive, especially at the beginning. I was told by my haem that positive or negative the treatment was the same. Kind regards Aime xx😺

[blulou in reply to Aime]

There many unresolved mysteries out there on the ninth chromosome.

[pastorterry]

I too have PV and am JAK2 negative. One doctor says I have primary PV and another says I have secondary PV. Seems the treatment are similar only those who are JAK2 negative can use the new drugs for treatment and most those who are negative these drugs have no effect on. A lot of people with PV don't get tested so doctors don't treat them differently. I read a study last year that said 95% of the people with PV are positive. Nothing was said about the other 5%.

[mol56]

I have E.T JAK NEGATIVE.

When I was diagnosed over 10 years ago, the JAK gene connection hadn't been made.

I had symptoms of E.T. ( extreme fatigue, headaches) and had a blood test which showed high platelets. This diagnosis was confirmed by a bone marrow biopsy and a scan of my spleen. I also had many blood tests which were sent to Addenbrooks hospital for research purposes.

I was checked for the JAK gene about 5 years ago and the negative result hasn't made any difference to my treatment as yet.

However, last year, I was tested for the Calr gene which came back positive. Again, this hasn't made any difference to my treatment or condition as yet.

I understand that it extremely rare to be both JAK NEG and Calr negative.

I find it a little strange now that everyone talks about the JAK GENE MUTATION as being the way they were diagnosed as I was under the impression that a bone marrow biopsy and blood tests and scans were the best way. Probably because that's how it was diagnosed back then!!

[mickey64 in reply to mol56]

Thanks my GP told me that the CALR is called the Philadelphia gene? have no idea why? I think most who test negative for the Jak 2 test positive something else. One question everyone talks about the spleen? how do they test for that? I did have a Pet/CT but the CT was without contrast, they do feel my stomach. would that Pet/CT see if I had an enlarged spleen what is the contrast between an enlarged spleen and ET? Sorry for all the questions but I am new in this process get down a lot just thinking about it and trying to learn as much as possible.

[mol56]

I had an ultra sound scan similar to those given in pregnancy but as this was 10 years ago, things may have changed. My spleen was only slightly enlarged.