Glycogen Storage Disease: Everything You Need to Know

Dr.Ajitabh Srivastava, 3 mins read

Glycogen Storage Disease: Everything You Need to Know:
Glycogen storage disease (GSD) is a group of rare inherited conditions that affect the body’s ability to use or store glycogen properly. Glycogen is a form of stored glucose that serves as an energy source. It is stored in the liver.

When the body needs more energy, certain enzymes in the body break down the glycogen to release necessary glucose. But when one or more of these enzymes are missing, the body faces difficulty using or storing glycogen. This leads to GSD, causing problems in the liver, muscles or other parts of the body.

Types:
There are several types of glycogen storage disease. Each one is grouped based on the missing enzyme. Thus, each type has different symptoms and requires different treatment.

There are several types of GSD - at least 19. But the most common include:

Type I: Also known as Gierke disease, it occurs when the body does not have the enzyme (glucose-6-phosphatase or glucose-6-phosphate transporter). This leads to glycogen buildup in the liver. This may cause an enlarged liver, low blood sugar and a swollen belly.

Type III: Also known as Forbes-Cori disease, it occurs when the body does not have enough glycogen debrancher enzyme. Because of this, glycogen does not fully break down and collects in the liver and muscle tissues. It causes symptoms like weak muscles, swollen belly and delayed growth.

Type IV: This type is also known as Andersen disease. It occurs due to a deficiency of glycogen branching enzymes. This leads to abnormal glycogen levels, which affects the immune system and liver problems like cirrhosis.

Symptoms:
Symptoms of glycogen storage disease can vary depending on the specific type and severity of the condition. The symptoms usually develop at the age of three to four months. The symptoms may include:

• Low blood sugar (hypoglycemia)
• An enlarged liver
• Muscle weakness
• Growth delays
• Uncomfortable feeling in hot weather
• Bruising too easily
• A swollen belly
• Muscle pain or cramping during exercise

Babies can also experience too much acid in the blood and high blood cholesterol levels.

Causes:
Glycogen storage disease is caused by mutations in genes that affect the enzymes involved in glycogen metabolism. These mutations result in glycogen accumulation in various tissues. This ultimately leads to the symptoms and complications associated with the condition.

Diagnosis:
Diagnosis typically involves a combination of medical history, physical examination, blood tests and other tests to measure enzyme levels and glycogen levels. Genetic testing may also be required to identify specific gene mutations, and imaging studies to evaluate the condition.

Management and treatment:
Treatment focuses on managing symptoms and preventing complications. This may include:

• Dietary modifications to regulate blood sugar levels
• Medications to address the problem and any underlying condition
• Enzyme replacement therapy (if required)
• Regular monitoring and follow-up care with the doctor

As it is a genetic problem, you can’t prevent it. What you can do is consider genetic counselling to understand the risk of developing this problem in the baby. Also, it is necessary to keep a watch on the symptoms to get the treatment at an earlier stage and manage the condition effectively.