Caring for someone with this diagnosis? Eleplan keeps diagnoses, medications, documents and every specialist in one plan.
Start free with EleplanGlycogen storage disease due to muscle glycogen phosphorylase deficiency
ORPHA:368Disease
Also called GSD due to muscle glycogen phosphorylase deficiency · GSD type 5 · GSD type V · Glycogen storage disease type 5 · Glycogen storage disease type V · Glycogenosis due to muscle glycogen phosphorylase deficiency · Glycogenosis type 5 · Glycogenosis type V · McArdle disease · Myophosphorylase deficiency
What it is
A form of glycogen storage disease (GSD) characterized by exercise intolerance and rhabdomyolysis episodes, due to a deficiency of the muscle isoform of glycogen phosphorylase.
Key facts
- Prevalence
- 1-9 / 1 000 000 (Spain)
- Age of onset
- Adolescent, Adult, Childhood
- Inheritance
- Autosomal recessive
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Very common80–99%
5Common30–79%
5These 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.
Gene
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.
Powered by Eleplan
A rare diagnosis is just the start. Eleplan keeps the whole care plan in one place.
Diagnoses, medications, documents, appointments, and the whole care team — organized and always in sync, so you are not retelling the same story to every new specialist. With Ellie, your AI care assistant, on top of it. Free to start.