Abby,

the currently available diagnostic tools neurologists have can't really differentiate between refractory autoimmune MG and CMS.

This is just something you have to accept and live with.

There are currently very few known genetic abnormalities known to cause MG, which explain only a small part of CMS cases. To me this is not very surprising given the fact that they look for those abnormalities only in proteins of the NMJ.

To complicate matters it is not rare to have an autoantibody directed at an abnormal protein. So, you may have both.