Glycogen Storage Disease Type I (Von Gierke Disease)

What is Glycogen Storage Disease Type I (Von Gierke Disease)?

Glycogen Storage Disease Type I, also called Von Gierke Disease, is a rare inherited condition. It affects how your body breaks down glycogen, a form of stored glucose that your body uses for energy. People with this condition lack a working enzyme called glucose-6-phosphatase. This enzyme is needed to release glucose from glycogen stores in the liver and kidneys.

Without this enzyme, glycogen builds up in the liver and kidneys instead of being converted to usable glucose. This causes low blood sugar between meals and leads to a buildup of harmful substances like lactic acid and uric acid. The condition is present from birth and requires lifelong management. Most children are diagnosed before age 1, though some cases are found later in childhood.

Von Gierke Disease is inherited in an autosomal recessive pattern. This means both parents must carry the gene mutation for a child to develop the condition. With proper treatment and monitoring, many people with this condition live active lives into adulthood.

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Symptoms

Severe low blood sugar that happens within a few hours of eating
Enlarged belly due to swollen liver
Slow growth and delayed puberty
Frequent nosebleeds or easy bruising
Doll-like face with full cheeks
Kidney problems that develop over time
High uric acid levels leading to gout-like symptoms
Extreme fatigue and weakness
Irritability when blood sugar drops
Seizures from very low blood sugar

Infants may show symptoms early with rapid breathing, sweating, or seizures from low blood sugar. Some people have milder symptoms that are not recognized until later in childhood.

Causes and risk factors

Glycogen Storage Disease Type I is caused by mutations in the G6PC or SLC37A4 genes. These genes provide instructions for making the glucose-6-phosphatase enzyme system. When this enzyme does not work properly, the liver cannot release glucose from glycogen stores. This leads to dangerous drops in blood sugar and a buildup of glycogen in tissues.

The condition is inherited when both parents carry one copy of the mutated gene. Each child of two carriers has a 25% chance of having the disease. Certain populations have higher carrier rates, including people of Ashkenazi Jewish descent. There are no lifestyle or environmental risk factors, as this is a genetic condition present from birth.

How it's diagnosed

Doctors diagnose Glycogen Storage Disease Type I through a combination of symptoms, blood tests, and genetic testing. Blood work typically shows very low glucose levels, high lactic acid, high triglycerides, and elevated uric acid. Rite Aid's testing panel includes uric acid monitoring, which is important for people with this condition. High uric acid is a hallmark feature that needs regular tracking.

Genetic testing confirms the diagnosis by identifying mutations in the G6PC or SLC37A4 genes. A liver biopsy may be done in some cases to measure enzyme activity, though genetic testing has largely replaced this. Imaging studies like ultrasound can show an enlarged liver and kidney changes. Early diagnosis is important for preventing dangerous drops in blood sugar and long-term complications.

Treatment options

Frequent meals and snacks to maintain stable blood sugar levels
Uncooked cornstarch supplements that provide slow-release glucose
Overnight feeding through a tube in some cases
Avoiding fasting for more than a few hours
Medications to lower uric acid levels and prevent gout
Medications to manage high cholesterol and triglycerides
Low-sugar, low-fat diet with careful carbohydrate timing
Regular monitoring of blood sugar, uric acid, and kidney function
Treatment for kidney disease if it develops
Working with a metabolic specialist and dietitian

Frequently asked questions

Glycogen Storage Disease Type I is a rare genetic condition where the body cannot break down stored glycogen into glucose. This causes dangerous drops in blood sugar and buildup of harmful substances like uric acid. It is present from birth and requires lifelong dietary management and monitoring.

Von Gierke Disease is caused by mutations in genes that make the glucose-6-phosphatase enzyme. Without this enzyme, the liver cannot release glucose from glycogen stores. The condition is inherited when a child receives a mutated gene from both parents.

The main symptoms include severe low blood sugar between meals, enlarged belly from liver swelling, slow growth, and fatigue. People may also have easy bruising, nosebleeds, and high uric acid that can cause gout. Symptoms often appear in the first year of life.

Diagnosis involves blood tests showing low glucose, high lactic acid, high triglycerides, and elevated uric acid. Genetic testing confirms the diagnosis by finding mutations in specific genes. Imaging studies may show an enlarged liver and kidney changes.

People with Von Gierke Disease have chronically high uric acid levels due to increased purine breakdown and impaired kidney excretion. This can lead to gout, kidney stones, and progressive kidney damage. Regular monitoring helps doctors adjust medications to prevent these complications.

There is no cure for this genetic condition at this time. However, with proper treatment and dietary management, many people live into adulthood with good quality of life. Treatment focuses on preventing low blood sugar and managing complications like high uric acid and kidney disease.

People need frequent meals and snacks to maintain stable blood sugar levels. Uncooked cornstarch is often used as it provides slow-release glucose overnight. The diet should be low in simple sugars and fats, with carefully timed complex carbohydrates to prevent blood sugar drops.

Blood tests are typically needed every 3 to 6 months to monitor uric acid, kidney function, liver enzymes, and cholesterol levels. More frequent testing may be needed in childhood or when adjusting treatments. Regular monitoring helps prevent long-term complications and guides medication adjustments.

Medications to lower uric acid, like allopurinol or febuxostat, are commonly used to prevent gout and kidney damage. Drugs to manage high cholesterol and triglycerides may also be needed. The main treatment is dietary, but medications help manage metabolic complications.

Long-term complications include kidney disease from high uric acid, liver tumors that can develop in adulthood, and gout. High triglycerides can increase heart disease risk. With proper monitoring and treatment, the risk of these complications can be reduced significantly.