Congenital myasthenia is an inherited disorder that affects the transmission of signals to the muscles. It results from a variety of genetic defects at the molecules associated with neuromuscular transmission. Congenital myasthenia is not the same as myasthenia gravis, which is an autoimmune disorder. More than a dozen congenital myasthenic syndromes have been classified. Symptoms are usually noticed in early childhood and include drooping eyelids, facial weakness, and limb weakness. Parents of children with congenital myasthenia frequently show no symptoms of the disorder

Anticholinesterase drugs, as well as guanidine and other drug therapy that facilitates neuromuscular transmission, may improve some symptoms of congenital myasthenia.

Several cases of congenital myasthenia improve or stabilize with drug therapy. In other cases, therapy is not effective. Adverse respiratory reactions may occur as a result of drug therapy, but they can be treated.

Prepared by the National Institutes of Health