What's Pompe disease?
Pompe disease (glycogen storage disease type II) is an inherited condition caused by deficiency of the enzyme acid alpha-glucosidase (GAA), so glycogen builds up in muscle and other tissues.
| Also indexed as | OMIM:232300, MONDO:0017694 |
|---|---|
| Features mapped | 13 |
| Treatments mapped | 3 |
| Published sources | 9 |
| Last reviewed | 2026-08-04 |
Signs and symptoms
Limb muscle weakness
In the later-onset form, weakness builds up gradually, affecting the limb and trunk muscles, which makes walking, climbing, and rising harder over time.
Cardiomegaly
In the severe infantile form, the heart muscle thickens and the heart becomes enlarged early in life.
Autosomal recessive inheritance
Pompe disease is inherited in an autosomal recessive pattern, needing a changed copy of the GAA gene from each parent.
Respiratory insufficiency
Pompe disease weakens the breathing muscles, including the diaphragm, so breathing problems are a central feature and a key reason for treatment and monitoring.
Exercise intolerance
Pompe disease is recognised in two main forms. The infantile-onset form involves almost no GAA enzyme activity, along with severe heart muscle disease and neurological problems. The late-onset form mainly involves impaired breathing and movement.
Young adult onset
The feature that distinguishes the infantile-onset and late-onset forms of pompe disease is heart muscle disease in the first year of life: it is present in the infantile-onset form and absent in the late-onset form.
Elevated circulating creatine kinase activity
Blood tests often show a raised creatine kinase (CK), an enzyme released by damaged muscle, which can be an early clue that prompts testing for Pompe disease.
Increased muscle glycogen content
When the GAA enzyme is missing or in short supply, glycogen builds up to harmful levels in almost all tissues of the body. The effects are most pronounced in heart and skeletal muscle and in the central nervous system.
Reduced muscle alpha-1,4-glucosidase activity
In pompe disease the activity of the enzyme acid alpha-glucosidase (GAA) is reduced. Because this enzyme normally clears glycogen inside cells, its deficiency leads to a harmful build-up of glycogen in multiple tissues.
Proximal muscle weakness
Weakness of the muscles closest to the trunk (proximal muscle weakness) is a core feature, alongside weakening of the muscles used for breathing.
Hypotonia
In the severe infantile form, babies are very floppy (severe hypotonia) in the first months of life, alongside heart muscle thickening.
Respiratory insufficiency due to muscle weakness
In the late-onset form of pompe disease, weakness develops mainly in the skeletal muscles and in the muscles used for breathing, and it tends to get worse over time. Symptoms can begin at any point from infancy through adulthood.
Muscle weakness
Muscle weakness is a defining feature and, in infants, can come with feeding difficulties.
How it is diagnosed
Glycogen storage disease II
Diagnosed using: Acid alpha-glucosidase (GAA) enzyme activity assay.
“…caused by deficiency of acid alpha-glucosidase (GAA), leading to pathological glycogen accumulation in multiple…”
Glycogen storage disease II
Diagnosed using: Newborn screening.
“Newborn screening (NBS) now allows for early detection and clinical monitoring in infants and children with late-onset Pompe disease (LOPD), potentially identifying those needing early enzyme replacement therapy (ERT).”
Treatment and management
What the research describes, not a recommendation. Treatment decisions belong with your clinician.
This covers treatments that appear in the published research mapped here. Investigational and experimental therapies are not included, so their absence is a boundary of this map, not a sign they do not exist.
Alglucosidase alfa
Alglucosidase alfa is an enzyme replacement therapy that supplies the missing GAA enzyme and is the main treatment for Pompe disease.
Used to help with: Glycogen storage disease II.
“- Source: Short-Term Intensive Avalglucosidase Alfa Regimen in Late-Diagnosed Infantile Pompe Disease: A Case Report. - Source ID / type: PMID:41718282 / peer_reviewed_study - Publication date: 2026 - Study design: Case Reports, Journal Article Sample size: ## Finding Background and Clinical Significance: Classic infantile-onset Pompe disease (IOPD) is the most severe form of Pompe disease, manifesting within the first months of life with hypertrophic cardiomyopathy and severe hypotonia.”
Enzyme replacement therapy
Enzyme replacement therapy (ERT) supplies a laboratory-made version of the missing GAA enzyme. In pompe disease it significantly improves survival and stabilizes motor function.
Used to help with: Glycogen storage disease II.
“Pompe disease is a rare, progressive lysosomal storage disorder caused by acid α-glucosidase deficiency, leading to glycogen accumulation, proximal muscle weakness, and respiratory decline. Enzyme replacement therapy (ERT) significantly improves survival and stabilizes motor function, but IgE-mediated hypersensitivity reactions (HSRs) can critically compromise treatment, posing a major clinical challenge.”
Avalglucosidase alfa
Avalglucosidase alfa is a newer, laboratory-made version of the human alpha-glucosidase enzyme used in enzyme replacement therapy for pompe disease. It was recently approved for use.
Used to help with: Glycogen storage disease II.
“Classic infantile-onset Pompe disease (IOPD) is the most severe form of Pompe disease, manifesting within the first months of life with hypertrophic cardiomyopathy and severe hypotonia. Avalglucosidase alfa is a next-generation recombinant human α-glucosidase that was recently approved for use.”
How to read the evidence labels
Where this comes from
This guide is built from 9 published source(s). Every claim above links back to one of them. Click any source ID to read the original on PubMed.
Take it further
Printed, source-linked documents built from this condition's graph — ready to bring to an appointment or attach to a coverage request. Every claim carries its published source, the same as this guide.