'Congenital myasthenic syndrome' is an inherited muscular disorder caused by genetic flaws at the
neuromuscular junction. The affects of the disease are similar to
Lambert-Eaton syndrome and
Myasthenia gravis, the difference being that LEMS and MG are
autoimmune disorders, but CMS is hereditary.
Symptoms and categories
The types of CMS are classified into three categories:
presynaptic,
postsynaptic, and
synaptic.
''Presynaptic'' syptoms include brief stops in breathing, weakness of the eye, mouth, and throat muscles. These symptoms often result in double vision and difficulty chewing and swallowing. ''Postsynaptic'' symptoms in infants include severe muscle weakness, feeding and respiratory problems, and delays in the ability to sit, crawl, and walk. Onset symptoms for all ages may include
droopy eyelids. A particular form of postsynaptic CMS (slow-channel CMS) includes severe weakness beginning in infancy or childhood that progresses and leads to loss of mobility and respiratory problems in adolescence or later life. ''Synaptic'' symptoms include early childhood feeding and respiratory problems, reduced mobility, curvature of the spine, and weakness, which causes a delay in
motor milestones.
Treatment
Treatment depends on the form (category) of the disease. Although symptoms are similar to myasthenia gravis, treatments used in MG are not useful in CMS. MG is treated with immunosuppressants, but the affects of CMS are not caused by the immune system, it is hereditary.
A form of presynaptic CMS is caused by an insufficient release of
acetylcholine (ACh) and is treated with cholinesterase inhibitors. Postsynaptic fast-channel CMS (ACh receptors do not stay open long enough) is treated with cholinesterase inhibitors and 3,4-diaminopyridine. Postsynaptic slow-channel CMS is treated with quinidine or fluoxetine, which plugs the ACh receptor. Synaptic CMS has no effective drug treatment.
References
★
Myasthenia gravis, Lambert-Eaton Myasthenic syndrome & Congenital Myasthenic Syndrome
★
About Congenital Myasthenic Syndrome From the
Mayo Clinic website
★
Treatment for Congenital Myasthenic Syndromes From the
Mayo Clinic website
See also
★
Congenital disorder
★
Myasthenia gravis
★
Lambert-Eaton syndrome
External links
Congenital Myasthenic Syndromes
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