Glycogen Storage Disease Type 6: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Glycogen Storage Disease Type 6?
A primary care doctor often notices the first signs and orders early tests. Care usually involves a metabolic geneticist or a liver specialist called a hepatologist, and a dietitian often helps families build meal plans. A direct primary care or concierge doctor can handle routine monitoring but would refer suspected or confirmed cases to a metabolic specialist.
What it is
Glycogen storage disease type 6, sometimes called Hers disease, is a rare inherited condition that affects how the body uses glycogen, a stored sugar kept in the liver and muscles for energy. People with this disease lack enough of an enzyme called liver glycogen phosphorylase, so the liver cannot break down glycogen into glucose and becomes enlarged.
Symptoms
Many children with this disease have few problems, and some are never diagnosed. The most common sign is an enlarged liver. Low blood sugar can happen after going without food, making a child feel shaky, sweaty, tired, or cranky. Some children grow more slowly than expected, and symptoms often get milder in adulthood.
Causes and who gets it
This disease is passed down in an autosomal recessive pattern, meaning a child must receive one changed gene, called PYGL, from each parent. The parents usually have no symptoms themselves. The disease is rare and affects boys and girls equally.
How doctors diagnose it
A doctor starts by examining the child and asking about symptoms and family history. Blood tests, ultrasound, and genetic testing can help confirm the diagnosis, and a liver biopsy is sometimes but not always needed.
Treatment
There is no cure, but most people do well with careful management. The main goal is to keep blood sugar steady with frequent meals and snacks that include complex carbohydrates. Some people drink a cornstarch mixture, which breaks down slowly and keeps blood sugar from dropping overnight or between meals. Doctors advise avoiding long periods without food and being careful with very hard exercise.
When to see a doctor
Talk to a doctor if a child has a swollen belly, slow growth, unusual tiredness, or shakiness and sweating that improve after eating. Seek care quickly for dark urine after exercise, since this can signal muscle breakdown. Early diagnosis makes it easier to plan meals and avoid low blood sugar episodes.
Common questions
Can people with glycogen storage disease type 6 live normal lives?
Most people with this disease have mild symptoms and do very well. With regular meals and follow-up care, many children grow up to be healthy adults. Outcomes differ from person to person.
Is this disease the same as other glycogen storage diseases?
No. There are several types, and each one involves a different enzyme. Type 6 mainly affects the liver and is usually milder than some other types.
Do both parents need to carry the gene?
Yes. Because the disease is autosomal recessive, a child needs one changed copy of the gene from each parent. Parents who each carry one changed copy usually have no symptoms.
Can adults find out they have this disease for the first time?
It is uncommon, but mild cases can go unnoticed for years. Some adults learn about it during testing for an enlarged liver or unusual blood test results.
Sources
- NIH Genetic and Rare Diseases Information Center - Glycogen storage disease, type VI
- MedlinePlus - Glycogen storage disease type 0: MedlinePlus Genetics
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
