Congenital myasthenic syndrome

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Congenital myasthenic syndrome

ORPHA:590Disease

Also called CMS

What it is

A rare genetic neuromuscular disease characterized by impaired transmission at the neuromuscular junction, typically presenting in infancy or childhood, although later onset is possible. The hallmark symptom is muscle fatigability, frequently accompanied by ocular manifestations (ptosis, ophthalmoparesis), bulbar involvement (dysphagia), a generalized weakness, which can lead to potentially life-threatening respiratory insufficiency.

Key facts

Prevalence
1-9 / 1 000 000 (Europe)
Age of onset
Infancy, Neonatal
Inheritance
Autosomal dominant, Autosomal recessive
Classified as
Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Genes reported in subtypes

COL13A1COLQLAMB2

Orphanet records these genes on 1 more specific entry under this disorder, not on this entry itself:

A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.

ICD-10 codes

G70.2ICD-10 names this disease exactly — shared with 4 other rare diseases

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references

GARD 11902MEDDRA 10083942MESH D020294MONDO 0018940OMIM 254190OMIM 254210OMIM 254300OMIM 601462OMIM 603034OMIM 605809OMIM 608930OMIM 608931OMIM 610542OMIM 614198OMIM 614750OMIM 615120OMIM 616040OMIM 616224OMIM 616227OMIM 616228OMIM 616304OMIM 616313OMIM 616314OMIM 616321OMIM 616322OMIM 616323OMIM 616324OMIM 616325OMIM 616326OMIM 616330OMIM 616720OMIM 617143OMIM 617239OMIM 618197OMIM 618198OMIM 618323OMIM 619461OMIM 620451OMIM 621455UMLS C0751882

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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