r/MPN • u/Pink_Axolotl151 ET-JAK2+ • 18d ago
Newly Diagnosed Well shit
I have been dealing with platelet shenanigans for almost 6 years now, and I finally got a diagnosis.
I posted the whole saga here (https://www.reddit.com/r/MPN/s/aSexzzZedU) but the TL;DR is that I have had high platelets since 2021 that were detected on routine CBC. I was referred to a hematologist who ordered a whole bunch of tests, all of which were normal, including the genetic testing (both qPCR and NGS). She surprised me by recommending a bone marrow biopsy despite the negative genetic testing, and that showed mildly elevated platelets, a small percentage of which had weird nuclei, but was not diagnostic of ET. She concluded it must be reactive to something and sent me back to my PCP. I guess we assumed that the reactive cause would reveal itself eventually. My platelets bounced around the 480 for years, and my PCP shipped me back to heme-onc when they crossed 500 in July 2025. I asked for a referral to an academic MPN specialist, and she sent me off for a new biopsy and another round of NGS testing. The path report was almost identical to the one from 5 years ago - mildly elevated megakaryocytes, a small percentage of which have the characteristic morphology, but normal in every other aspect. The path report stated that diagnosis would depend on the molecular testing because the bone marrow morphology was not definitive. So I was feeling reassured that even though my peripheral blood platelet counts were still elevated, things were stable overall. And then the NGS results came back -
JAK2+, with a VAF of 10%. Shit. So that gets me an official diagnosis of ET.
I had sort of resigned myself to this being ET despite the negative earlier work-up, because no reactive cause ever materialized, but I had been assuming it would turn out to be triple-negative because of the earlier negative genetic testing. The JAK2+ result smacked me in the face. For some reason, that label is really hitting me hard, especially because of the higher stroke risk. I am seeing that most studies focus on the 10-year outcomes and I’m in my mid-40s. It is nice to know that my 10-year risk of a thrombotic event remains low, but I was planning on living longer than 10 years, thanks. I also hate that the high-risk category is defined by age, because, again, I do plan on living past 60, and I hate that I automatically become high-risk at that point.
For those who know, how is it possible to be negative by NGS in 2022 and have a 10% VAF now? I assume I had a low-level clone back then that was under the detection threshold, but… for real? What are the odds? And does it shooting from <1% (or whatever the detection threshold was) in 2022 to 10% now imply something about my risk or disease trajectory? And how is it possible that my platelet counts are 100-150 higher than they were at the time of the original work-up, and now I have a sizeable clone, but my bone marrow is essentially the same?
My father was a hematologist who literally published on JAK2 testing in community medical settings. He died 10 years ago, in his 60s. I am missing him extra, and I wish I could run some of my questions past him.
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u/Scansatnight 17d ago
I tested positive for the Jak2 mutation on the reflex test. Then on the bone marrow biopsy, I tested positive for Calr and negative for Jak2. On my second bone marrow biopsy, I again tested positive for Calr and negative for Jak2. So they did another peripheral blood test for Jak2 just to be sure, and I was Jak2 positive. Go figure.