Structured, medically reviewed information about congenital myasthenic syndromes, clearly separated from personal experience reports.
Congenital myasthenic syndromes (CMS) are a heterogeneous group of rare inherited disorders affecting neuromuscular transmission. They are caused by mutations in genes coding for proteins at the neuromuscular junction. The result is impaired signal transmission between nerve and muscle.
CMS includes more than 30 genetically defined subtypes. Frequently affected genes include CHRNE, DOK7, RAPSN, COLQ, and GFPT1. Each subtype can present differently and respond differently to treatment, which makes genetic diagnosis essential.
Typical symptoms include fatigue-related muscle weakness, ptosis, ophthalmoplegia, and swallowing or breathing difficulties. Some subtypes show episodic apneas in childhood. Severity varies widely from mild weakness to severe disability.
Treatment is genotype-specific. Depending on subtype, pyridostigmine, salbutamol, ephedrine, or amifampridine can be used. Some drugs are contraindicated in certain subtypes, for example cholinesterase inhibitors in COLQ-CMS. Incorrect treatment can worsen symptoms.
Yes. In most cases CMS is inherited in an autosomal recessive pattern, meaning both parents carry one altered copy of the gene without being affected themselves. Some subtypes follow autosomal dominant inheritance.
Diagnosis combines clinical assessment, electrophysiology, and genetic testing. CMS is typically AChR antibody negative, and confusion with seronegative myasthenia gravis is common.
Yes. Recent studies indicate that a meaningful share of adults labeled with seronegative myasthenia gravis may actually have CMS, so first diagnosis in adulthood is not rare.
There is currently no cure. Treatment focuses on symptom control and quality of life, and with appropriate therapy functional outcomes can often improve significantly.
The content on this page is for general information only and does not replace medical advice. For individual health questions, consult a specialist in neuromuscular disorders.