glycogen storage disease due to muscle and heart glycogen synthase deficiency
Findings
No curated finding names glycogen storage disease due to muscle and heart glycogen synthase deficiency yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
A glycogen storage disease characterized by muscle and heart glycogen deficiency. It has been described in three siblings (two brothers and their younger sister). The older brother died at 10.5 years of age as a result of sudden cardiac arrest and the younger brother presented with hypertrophic cardiomyopathy, abnormal heart rate and blood pressure during exercise, and muscle fatigability. The sister showed no symptoms but a lack of glycogen was identified through muscle biopsy. The syndrome is caused by homozygous missense mutations in the gene encoding muscle glycogen synthase.
Definition from the Mondo Disease Ontology (MONDO:0012693), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Juvenile onset · Childhood onset
HPO, annotations 2026-09-02
Features
37 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.
- AstheniaHPOHP:0025406
- 1 of 1 reported patient
- Bilateral tonic-clonic seizureHPOHP:0002069
- 1 of 1 reported patient
- Bilateral tonic-clonic seizure with generalized onsetHPOHP:0025190
- 1 of 1 reported patient
- Cardiac arrestHPOHP:0001695
- 1 of 1 reported patient
- Cardiomyocyte hypertrophyHPOHP:0031319
- 1 of 1 reported patient
- Decreased muscle glycogen contentHPO
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.
- GYS1HGNC:4706
- Definitive · ClinGen · Autosomal recessive · 2024
- Strong · Genomics England PanelApp · Autosomal recessive · 2020
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2018
- Strong · PanelApp Australia · Autosomal recessive · 2025
- Supportive · Orphanet · Autosomal recessive · 2021
Where it sits
- A kind of
Other names
7 names
Resolves to: glycogen storage disease due to muscle and heart glycogen synthase deficiency
- Also called
- glycogen storage disease due to glycogen synthase deficiency of heartglycogen storage disease type 0bglycogenosis due to muscle and heart glycogen synthase deficiencyglycogenosis type 0bGSD due to muscle and heart glycogen synthase deficiencyGSD type 0bheart glycogen storage disease due to glycogen synthase deficiency