There is no antibody test for CMS because congenital myasthenic syndromes (a group of over 100 mutations) is a genetic disease, not autoimmune. There are blood tests to look for the mutations.

Congenital MG simply means that you've had autoimmune MG since birth.

CMS is "congenital" because you've had your "genes" since birth.

CMS and MG have different causes but can have similar symptoms.

Some people with CMS have too much acetylcholine or none at all. Others are like MG and don't have enough.

Does that clear it up?