Hi, JennyG. Welcome!

MuSK MG is different than AChR MG and can be hard to manage.

http://neuromuscular.wustl.edu/mtime/mgdrug.html#musk

Your Mom's doctor could speak to Dr. Charles Harper at Mayo in Rochester. He has a great deal of experience treating MG patients with Rituxin/Rituximab.

It has really been helping MG patients. Yes, there is a risk of cancer, as there is with any immunosuppressant.

What other meds is she on? Have they tested for any other conditions which might be coexisting (i.e., B12 or D deficiencies, thyroid issues, other AIs, etc.)?

I hope she can find a treatment regimen that works for her! It does help to consult with other MG experts.

Annie