myotonic dystrophy type 1
Findings
No curated finding names myotonic dystrophy type 1 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Steinert disease, also known as myotonic dystrophy type 1, is a muscle disease characterized by myotonia and by multiorgan damage that combines various degrees of muscle weakness, arrhythmia and/or cardiac conduction disorders, cataract, endocrine damage, sleep disorders and baldness.
Definition from the Mondo Disease Ontology (MONDO:0008056), read 2026-09-29. CC BY 4.0.
Features
108 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.
- Muscle weaknessHPOHP:0001324
- Obligate (100% of cases)
- Cardiac conduction abnormalityHPOHP:0031546
- Very frequent (80% to 99% of cases)
- Distal muscle weaknessHPOHP:0002460
- Very frequent (80% to 99% of cases)
- EMG: myotonic dischargesHPOHP:0100284
- Very frequent (80% to 99% of cases)
- Excessive daytime somnolenceHPOHP:0001262
- Frequent (30% to 79% of cases)
- Very frequent (80% to 99% of cases)
- Myotonia with warm-up phenomenonHPOHP:0003740
- Very frequent (80% to 99% of cases)
- Posterior subcapsular cataractHPOHP:0007787
- Very frequent (80% to 99% of cases)
- Abnormal rapid eye movement sleepHPOHP:0002494
- Frequent (30% to 79% of cases)
- Abnormality of masticatory muscleHPOHP:0410011
- Frequent (30% to 79% of cases)
- Atrial fibrillationHPOHP:0005110
- 1 of 11 reported patients
- Frequent (30% to 79% of cases)
- Atypical behaviorHPOHP:0000708
- Frequent (30% to 79% of cases)
- Cognitive impairmentHPOHP:0100543
- Frequent (30% to 79% of cases)
Show the remaining 96
- Fatigable weakness of bulbar musclesHPOHP:0030192
- Frequent (30% to 79% of cases)
- FatigueHPOHP:0012378
- Frequent (30% to 79% of cases)
- Foot dorsiflexor weaknessHPOHP:0009027
- Frequent (30% to 79% of cases)
- Gait disturbanceHPOHP:0001288
- Frequent (30% to 79% of cases)
- Impairment in personality functioningHPOHP:0031466
- Frequent (30% to 79% of cases)
- MyalgiaHPOHP:0003326
- Frequent (30% to 79% of cases)
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.
- DMPKHGNC:2933
- Definitive · G2P · Autosomal dominant · 2018
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal dominant · 2022
Where it sits
- Narrower terms (1)
Other names
8 names
Resolves to: myotonic dystrophy type 1
- Also called
- DM1DMPK myotonic dystrophydystrophia myotonicaMD1myotonic dystrophy caused by mutation in DMPKSteinert diseaseSteinert myotonic dystrophy syndromeSteinert syndrome