When and how do you perform genetic testing for congenital myasthenia gravis in seronegative cases?

I believe that these congenital myasthenic syndromes can start at birth or early childhood, as we are all familiar with muscular weakness, particularly extraocular muscles, and bulbar, which is fatigable, worsening with physical activity, and there > 30 genes responsible, and symptoms vary by the Gene affected. Additional features that clue are skeletal abnormalities, hearing loss, shortness of breath, seizures, etc.

Most commonly inherited as an autosomal recessive.

A thorough neurological physical exam, blood tests that show the absence of the antibodies, repetitive nerve stimulation that supports fatigability, and then genetic testing, particularly if these clinical features are present, is my approach to testing these rare disorders.

Ge...