King-Denborough syndrome
Findings
No curated finding names King-Denborough syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
A rare genetic non-dystrophic myopathy characterized by the triad of congenital myopathy, dysmorphic features and susceptibility to malignant hyperthermia. Patients present with a wide phenotypic range, including delayed motor development, muscle weakness and fatigability, ptosis and facies myopathica (with or without creatine kinase elevations), skeletal abnormalities (e.g. short stature, scoliosis, kyphosis, lumbar lordosis and pectus carinatum/excavatum), mild dysmorphic facial features (e.g. hypertelorism, down-slanting palpebral fissures, epicanthic folds, low set ears, micrognathia), webbing of the neck, cryptorchidism, and a susceptibility to malignant hyperthermia and/or rhabdomyolysis due to intensive physical strain, viral infection or statin use.
Definition from the Mondo Disease Ontology (MONDO:0020485), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal dominant inheritance
- Onset and course
- Juvenile onset · Fetal onset · Childhood onset
HPO, annotations 2026-09-02
Features
38 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.
- Bilateral cryptorchidismHPOHP:0008689
- 1 of 1 reported patient
- Bilateral ptosisHPOHP:0001488
- 1 of 1 reported patient
- Breech presentationHPOHP:0001623
- 1 of 1 reported patient
- Broad nasal tipHPOHP:0000455
- 1 of 1 reported patient
- Decreased fetal movementHPOHP:0001558
- 1 of 1 reported patient
- Deep philtrumHPOHP:0002002
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.
- RYR1HGNC:10483
- Supportive · Orphanet · Autosomal dominant · 2021
Where it sits
Other names
1 name
Resolves to: King-Denborough syndrome
- Also called
- Koussef-Nichols syndrome