Positive MUSK antibodies, followed by 2 negative tests, then enlarged thymus.
I have had strange weakness symptoms on and off for about 10 months. My doctors checked for M.S and a few other things , all of which came back negative. One doctor said "let's do a last ditch effort here and runs some tests for rare diseases", and that is where I came back positive for MUSK antibodies and negative for the other MG antibodies. He was not convinced I had the symptoms for it and said let's recheck it in a month. On the next test, my MUSK antibodies were negative. He was confused and did yet another retest 3 weeks later and it was negative again.
He wanted to check my thymus even though thymus involvement in MUSK is not common, but to his and my surprise, I don't have a thyoma but I do have "thymus hyperplasia" .
I am very confused. Isn't the thymus only involved in non-MUSK cases? Also, why would I have 2 negative antibody tests after the initial positive one?
You are justified in your confusion. While researchers generally distinguish between MUSK-related and other forms of MG, there are still quesitons and the levels of confidence in the test can vary. And about ten percent of the known cases show no antibody evidence at all. Keep in close contact with a good neuro-muscular specialist as you progress (and we have confidence you will!) Juliana (myasthenia-gravis.com team)
Hi
, I'm so sorry you have experienced these confusing test results. I can imagine it's frustrating not to have clear answers despite multiple tests and doctors visits. Do you feel comfortable asking your doctor for clarification on these results? It may be worth seeing another doctor for a second opinion as well - the Myasthenia Gravis Foundation of America has a list of MG specialists who have experience working with people with MG (https://myasthenia.org/Professionals/Finding-MG-Care-Providers) In the meantime, other community members may chime in here if they have experience with mixed test results. Sending warm thoughts your way. I know feeling stuck without answers can be so unsettling, but please know this community is here for you. Hoping you find relief soon. Best, Lauren (Myasthenia-Gravis.com Team)
