Annie may have figured it out for me. Somewhere on this board (this thread? a different?), she mentioned an antibody test for congenital MG, and I believe that's what I have. I've had typically mild symptoms of MG since at least age 3, as well I have Autoimmune Polyglandular Syndrome (APS) Type 3C, which is hereditary & closely tied to MG.

I've mentioned APS and the "age 3" business to every doctor I've seen, but they were as ignorant as me in the sense none of us knew there was an antibody test for it.

KNOWLEDGE IS POWER!!