Overview
Glycogen storage disease due to acid maltase deficiency, also known as Pompe disease or glycogen storage disease type II (GSD II), is a rare inherited metabolic disorder caused by mutations in the GAA gene, which encodes the lysosomal enzyme acid alpha-glucosidase (acid maltase). This enzyme is responsible for breaking down glycogen within lysosomes. When the enzyme is deficient or absent, glycogen accumulates progressively in cells throughout the body, particularly in skeletal muscle, cardiac muscle, and smooth muscle, leading to cellular damage and organ dysfunction. Pompe disease presents as a clinical spectrum ranging from a severe infantile-onset form to milder late-onset forms. The classic infantile form typically manifests within the first few months of life with profound hypotonia (floppy baby), severe hypertrophic cardiomyopathy, feeding difficulties, respiratory distress, failure to thrive, and hepatomegaly. Without treatment, infantile-onset Pompe disease is usually fatal within the first year of life due to cardiorespiratory failure. The late-onset form (childhood, juvenile, or adult onset) is characterized by progressive proximal muscle weakness, particularly affecting the limb-girdle and respiratory muscles, without significant cardiac involvement. Patients often develop respiratory insufficiency, which may be the presenting symptom, along with difficulty walking, climbing stairs, and performing daily activities. The primary treatment for Pompe disease is enzyme replacement therapy (ERT) with recombinant human acid alpha-glucosidase (alglucosidase alfa, marketed as Myozyme/Lumizyme, and the next-generation avalglucosidase alfa, marketed as Nexviazyme). ERT has significantly improved survival and cardiac outcomes in infantile-onset patients and has been shown to stabilize or slow disease progression in late-onset patients. Supportive care includes respiratory support (including ventilatory assistance), physical therapy, occupational therapy, nutritional management, and regular monitoring of cardiac and pulmonary function. Gene therapy approaches are currently under investigation in clinical trials.
Also known as:
Clinical phenotype terms— hover any for plain English:
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Variable
Can begin at different ages, from infancy through adulthood
FDA & Trial Timeline
10 eventsUniversity of Missouri-Columbia — NA
Denali Therapeutics Inc. — PHASE1
AskBio Inc — PHASE1, PHASE2
Shionogi — PHASE2
Genzyme, a Sanofi Company — PHASE4
Oculox Technologies SA — NA
Erasmus Medical Center — PHASE4
GeneCradle Inc — PHASE1, PHASE2
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
4 availableOmeprazole
Maintenance of healing of EE due to acid-mediated GERD in patients 2 years of age and older
Pombiliti and Opfolda
in combination with Pombiliti, for the treatment of adult patients with late-onset Pompe disease (lysosomal acid alpha-glucosidase [GAA] deficiency) weighing greater than or equal to 40 kg and who are…
in combination with Pombiliti, for the treatment of adult patients with late-onset Pompe disease (lysosomal acid alpha-glucosidase [GAA] deficiency) weighing greater than or equal to 40 kg and who are not improving on their current enzyme replacement therapy (ERT)
Nexviazyme
Treatment of patients 1 year of age and older with late-onset Pompe disease (lysosomal acid alpha-glucosidase [GAA] deficiency)
Myozyme
Myozyme for use in patients with Pompe disease (GAA deficiency). Alglucosidase alfa has been shown to improve ventilator-free survival in patients with infantile onset Pompe disease as compared to an …
Myozyme for use in patients with Pompe disease (GAA deficiency). Alglucosidase alfa has been shown to improve ventilator-free survival in patients with infantile onset Pompe disease as compared to an untreated historical control, whereas use of Alphaglucosidase in patients with other forms of Pompe disease has not been adequately studied to assure safety and efficacy.
Rare Disease Specialist
Rare Disease Specialist
Treatment Centers
8 centersUC Davis MIND Institute- Site Number : 840010
📍 Sacramento, California
University of California at Irvine- Site Number : 840036
📍 Irvine, California
University of Arizona- Site Number : 840015
📍 Tucson, Arizona
Southern California Permanente Medical Group- Site Number : 840108
📍 Los Angeles, California
University of California at San Diego- Site Number : 840007
📍 San Diego, California
University of Arkansas for Medical Sciences- Site Number : 840113
📍 Little Rock, Arkansas
Phoenix Children's Hospital- Site Number : 840003
📍 Phoenix, Arizona
USC Health Sciences Center Dept of Genetics- Site Number : 840082
📍 Los Angeles, California
Financial Resources
1 resourcesTravel Grants
No travel grants are currently matched to Glycogen storage disease due to acid maltase deficiency.
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4 articlesCaregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
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Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Common questions about Glycogen storage disease due to acid maltase deficiency
What is Glycogen storage disease due to acid maltase deficiency?
Glycogen storage disease due to acid maltase deficiency, also known as Pompe disease or glycogen storage disease type II (GSD II), is a rare inherited metabolic disorder caused by mutations in the GAA gene, which encodes the lysosomal enzyme acid alpha-glucosidase (acid maltase). This enzyme is responsible for breaking down glycogen within lysosomes. When the enzyme is deficient or absent, glycogen accumulates progressively in cells throughout the body, particularly in skeletal muscle, cardiac muscle, and smooth muscle, leading to cellular damage and organ dysfunction. Pompe disease presents
How is Glycogen storage disease due to acid maltase deficiency inherited?
Glycogen storage disease due to acid maltase deficiency follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
Are there clinical trials for Glycogen storage disease due to acid maltase deficiency?
Yes — 20 recruiting clinical trials are currently listed for Glycogen storage disease due to acid maltase deficiency on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Glycogen storage disease due to acid maltase deficiency?
25 specialists and care centers treating Glycogen storage disease due to acid maltase deficiency are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.
What treatment and support options exist for Glycogen storage disease due to acid maltase deficiency?
2 patient support programs are currently tracked on UniteRare for Glycogen storage disease due to acid maltase deficiency. See the treatments and support programs sections for copay assistance, eligibility, and contact details.