My gastric doctor ran a gene test on me because 10 years ago I had a blood clot to my liver. No one ever knew why I got the clot. He found last month that I have the JAK2 gene. Does this mean I have an MPN? All bloodwork is in normal range and has been for the past decade. However I do have an enlarged spleen from the blood clot
Does it help to have a bone biopsy? Or can people with Jak2 not get a MPN?
Any help would be great!
Thank you,
Marley
Written by
Gavitian
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With the JAK2 mutation present and a history of thrombosis, then suspicion of a MPN would make sense. It certainly is something to follow up on with a MPN-expert doc. Be aware that since MPNs are rare disorders, many docs, even hematologists, do not have the KSAs to provide optimal care. Here is a list of patient recommended MPN-expert docs mpnforum.com/list-hem/ .
Along the way on this journey, do look into what the JAK Mutant Allele burden is and how it may play a role in what you experience. Basically, the lower the percentage of the allele burden, the less symptomatic you will likely be.
Thank you for your response. We live in the DC area and I have set up an appointment with a MPN specialist at John Hopkins. However, it’s a five month wait.
I did find out today that my allele burden is 27. I have no idea what that means though. Also, my type of JAK2 is V617F. I was told that is the common one? My hematologist is very helpful but fully admits he is not a specialist in this. He also is encouraging me to head to John Hopkins. They have put me on a low doseblood thinner also since I had the blood clot many years ago and are now finding the JAK2.
How did you get into Hopkins with normal bloodwork? Normal as in normal CBC results. I live a few miles away from Hopkins and was referred there by my doctor. Hopkins wouldn't even make an appt with me until I could provide abnormal bloodwork for 2 consecutive months even though I have tested positive for CALR and have had abnormal bloodwork for 16 years. No problem I thought. First bloodwork was abnormal. Second bloodwork came back normal for the first time in 16 years making we worry about progression to MF. But no appt could be made...because the labwork was normal. Maybe you got in bc of your history of clots.
I suspect that Gavitian was seen due to the hx of thrombosis and a mutant allele burden enough enough to trigger PV. MPNs are complex and some MPNers have a unique presentation.
Well, I'm not sure yet. I have an appt next week for more bloodwork. I am CALR positive so I shouldn't be having a normal platelet count. Unless it was a lab error. One of the signs of MF is changes in your blood such as a sudden normalization usually followed by a trend downward. If my next platelet count is even lower than I will be more suspicious. Or if I start to see a downward trend in my RBC suggesting oncoming anemia. I haven't had a normal platelet count in 16 years.
Also, being CALR positive makes my chances of my ET progressing to MF at 25 percent. But the good news is CALR positive MF tends to not be very aggressive. I'm on no treatment for my ET so that is why the sudden reversal in numbers alarmed me. My only other explanation I can come up with is I started a medication for my pain some months back and maybe it had the side effect of lowering my platelets.
I am also seen at Johns Hopkins, by Dr. Spivak - the Director of the MPN Clinic. This is a great place to receive care. Dr. Spivak works with me and my local (Loudoun County based) hematologist (who in not a MPN expert - but is a great doc). Definitely the right place to go.
A mutant allele burden of 27% is significant. I am JAK2+PV with a burden of 25%. generally speaking, people with a mutant allele burden of less than 50% will be more mildly effected. The reality is more complicated than that, but it is a good rule-of-thumb. Broadly speaking, people with ET will have the lowest, MF the highest, and PV in the middle - mutant allele burden. The role of the mutant allele burden is emerging research and not all docs are up on it, so some pay no attention to it. I do think it is important to know and that it does have a bearing on your prognosis and treatment.
I have never seen an hard and fast direct line correlation between the mutant allele burden and a specific MPN diagnosis. MPN diagnosis is made based on levels of blood cell types, mutation status, and sometimes bone marrow morphology. Thrombocytosis alone would be ET. Erythrocytosis alone or in combination with thrombocytosis or leukocytosis would be PV. There are also non-specified MPNs.
I have seen references to the JAK2 mutation doing something more than just increasing hematopoiesis. There is some thinking that it may also increase the likelihood of a thrombotic event not just by elevating platelets, but by elevating their tendency to stick together. The coagulation cascade is quite complex and there are a number of factors that influence it.
This is all something to talk to the MPN-expert doc about. It may be that you have a more unique presentation of a MPN and do not fit neatly into a PV or ET diagnosis. These are rare disorders and each of presentations can be unique.
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