congenital myasthenic syndrome 21
Findings
No curated finding names congenital myasthenic syndrome 21 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Any congenital myasthenic syndrome in which the cause of the disease is a mutation in the SLC18A3 gene.
Definition from the Mondo Disease Ontology (MONDO:0014983), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Infantile onset
HPO, annotations 2026-09-02
Features
17 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Exercise intoleranceHPOHP:0003546
- 2 of 2 reported patients
- OphthalmoplegiaHPOHP:0000602
- 2 of 2 reported patients
- PtosisHPOHP:0000508
- 2 of 2 reported patients
- ApneaHPOHP:0002104
- 1 of 2 reported patients
- CyanosisHPOHP:0000961
- 1 of 2 reported patients
- Easy fatigabilityHPOHP:0003388
- 1 of 2 reported patients
- Fatigable weakness of skeletal musclesHPOHP:0030197
Show the remaining 5
- Meconium ileusHPOHP:0004401
- 1 of 2 reported patients
- Respiratory insufficiencyHPOHP:0002093
- 1 of 2 reported patients
- Weakness of facial musculatureHPOHP:0030319
- 1 of 2 reported patients
- FatigueHPOHP:0012378
- Gait disturbanceHPOHP:0001288
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- SLC18A3HGNC:10936
- Strong · Genomics England PanelApp · Autosomal recessive · 2021
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2018
- Strong · PanelApp Australia · Autosomal recessive · 2025
- Limited · Ambry Genetics · Autosomal recessive · 2019
Where it sits
Other names
5 names
Resolves to: congenital myasthenic syndrome 21
- Also called
- CMS21congenital myasthenic syndrome caused by mutation in SLC18A3congenital myasthenic syndrome type 21myasthenic syndrome, congenital, 21, presynapticSLC18A3 congenital myasthenic syndrome