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Start free with EleplanPostsynaptic congenital myasthenic syndrome
ORPHA:98913Etiological subtype
What it is
Orphanet has not published a description for this disease yet. The identifiers, classification and cross-references below are still current.
Key facts
- Age of onset
- Infancy, Neonatal
- Inheritance
- Autosomal recessive
- Classified as
- Etiological subtype
Recorded for the broader condition
- Prevalence
- 1-9 / 1 000 000 (Europe)Congenital myasthenic syndrome
Orphanet records these for the broader condition rather than for this specific form. They are a starting point, not a figure for this subtype — subtypes often differ, and some are defined by being rarer than the condition they sit under.
Signs and symptoms
Common30–79%
21- Abnormality of eye movement
- Abnormality of masticatory muscle
- Abnormality of the musculature of the upper limbs
- Decreased miniature endplate potentials
- Decreased size of nerve terminals
- Easy fatigability
- EMG: decremental response of compound muscle action potential to repetitive nerve stimulation
- EMG: myopathic abnormalities
- Facial palsy
- Fatigable weakness of neck muscles
- High palate
- Muscle weakness
- Neck flexor weakness
- Ophthalmoparesis
- Ptosis
- Reduced tendon reflexes
- Shoulder girdle muscle weakness
- Skeletal muscle atrophy
- Type 1 muscle fiber predominance
- Upper limb muscle weakness
- Weakness of the intrinsic hand muscles
Sometimes5–29%
16- Ankle weakness
- Cyanosis
- Delayed gross motor development
- Diplopia
- Drowsiness
- Exertional dyspnea
- Fatigable weakness of respiratory muscles
- Hip flexor weakness
and 8 more in this range
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
Orphanet records these genes on 5 more specific entries 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
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
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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