Testing negative for JAK2

About 50% of people with ET and MF, and 3% of people with PV test negative for the JAK2 mutation. It isn’t yet clear whether JAK2 negative patients carry other, different mutations that cause the disease.

It can be a bit disconcerting to learn that you do not have the mutation, and would possibly not be able to receive the new medications if they become available, although it’s not certain yet whether such drugs would be effective on all MPD patients. The good news for JAK2 negative patients is that the same techniques used to discover the JAK2 mutation are now being used to reveal other defects along the stem cell communications pathway.