Overview
Glycogen storage disease (GSD) is a group of inherited conditions where the body cannot properly store or break down glycogen — a form of sugar that the body uses for energy. Normally, glycogen is stored in the liver and muscles and released when the body needs fuel. In GSD, a missing or faulty enzyme disrupts this process, causing glycogen to build up in harmful amounts or preventing the body from releasing energy when it needs it most. There are more than a dozen different types of GSD, each caused by a different enzyme problem and affecting different parts of the body. Some types mainly affect the liver, causing low blood sugar and a swollen belly. Others affect the muscles, leading to weakness, cramps, and exercise intolerance. Some types, like Pompe disease (GSD type II), can affect the heart as well. Symptoms can range from mild to life-threatening depending on the type. Treatment varies by type but often includes careful dietary management — such as eating frequent meals or using cornstarch to keep blood sugar stable — and in some cases, enzyme replacement therapy (ERT). For Pompe disease, alglucosidase alfa (Myozyme/Lumizyme) is an FDA-approved ERT. Research into gene therapy and other targeted treatments is ongoing, offering hope for better options in the future.
Also known as:
Key symptoms:
Low blood sugar (hypoglycemia), especially when fastingEnlarged liver (belly looks swollen or rounded)Muscle weakness or poor muscle toneMuscle cramps or pain during or after exerciseExtreme tiredness or fatigueSlow growth or short stature in childrenExercise intolerance — getting worn out very quicklyDark or cola-colored urine after exercise (in some types)Heart problems or enlarged heart (in some types)Breathing difficulties (in Pompe disease)High levels of fats in the blood (elevated triglycerides)Kidney problems (in some types)Delayed motor milestones in infants
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
5 eventsConnecticut Children's Medical Center
Insel Gruppe AG, University Hospital Bern — NA
Institute of Liver and Biliary Sciences, India
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Glycogen storage disease.
5 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Rare Disease Specialist
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Glycogen storage disease.
Community
No community posts yet. Be the first to share your experience with Glycogen storage disease.
Start the conversation →Latest news about Glycogen storage disease
Disease timeline:
New recruiting trial: Dietary Treatment Strategies and Metabolic Control in Glycogen Storage Disease Type I
A new clinical trial is recruiting patients for Glycogen storage disease
New recruiting trial: 'Glycogen Storage Diseases (GSDs) in Indian Children- Establishing an Indian GSD (I-GSD) Registry'
A new clinical trial is recruiting patients for Glycogen storage disease
New recruiting trial: Accuracy of Lactate Meter in GSDIa
A new clinical trial is recruiting patients for Glycogen storage disease
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
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.
Questions for your doctor
Bring these to your next appointment
- Q1.Which specific type of glycogen storage disease do I (or my child) have, and what does that mean for our daily life?,What dietary changes or feeding schedule do we need to follow, and can we work with a metabolic dietitian?,Are there any FDA-approved treatments or clinical trials available for this type of GSD?,What are the signs of a medical emergency, and what should we do if one happens at home or school?,What long-term complications should we watch for, and how often do we need monitoring tests?,Should other family members be tested for this condition?,Are there any restrictions on physical activity, and what kind of exercise is safe?
Common questions about Glycogen storage disease
What is Glycogen storage disease?
Glycogen storage disease (GSD) is a group of inherited conditions where the body cannot properly store or break down glycogen — a form of sugar that the body uses for energy. Normally, glycogen is stored in the liver and muscles and released when the body needs fuel. In GSD, a missing or faulty enzyme disrupts this process, causing glycogen to build up in harmful amounts or preventing the body from releasing energy when it needs it most. There are more than a dozen different types of GSD, each caused by a different enzyme problem and affecting different parts of the body. Some types mainly af
How is Glycogen storage disease inherited?
Glycogen storage disease 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?
Yes — 5 recruiting clinical trials are currently listed for Glycogen storage disease 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?
22 specialists and care centers treating Glycogen storage disease are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.