How do you get GSD?

Glycogen storage disease (GSD) is a recessive genetic disorder passed down when an individual inherits two copies of an altered gene for the same trait, one from each parent. If an individual inherits one normal gene and one gene for the disease, the person will be a carrier for GSD, but usually will not show symptoms. The risk for two carrier parents to both pass the altered gene and have an affected child is 25% with each pregnancy.

Can you grow out of GSD?

No. Because it is an inherited, metabolic disease, individuals with GSD will have it for their entire lives.

Are there different types of GSD? What’s unique about type 3?

There are several types of glycogen storage disease though all involve the liver and/or muscles. Type 3 GSD, also known as Forbes-Cori disease affects the liver, heart, skeletal muscles and blood cells.

How is type 3 GSD treated?

Dietary management is the cornerstone of treating GSD3. Ingesting raw cornstarch every three to four hours provides the body with a source of energy in the form of a slow release carbohydrate. Most often, this is the primary carbohydrate that individuals with GSD consume. Other carbohydrates and sugar in crackers, pasta, bread, rice, fruit, cookies, ice cream are avoided.

In 1982, “cornstarch therapy” was introduced to GSD patients as a way to maintain normal blood sugar levels for extended periods of time. Because cornstarch is a complex, slow-releasing carbohydrate, patients could ingest carefully measured doses of uncooked Argo cornstarch and keep blood sugar levels stable for three to hours hours.

In 2012, the FDA approved Glycosade for the dietary management of GSD. Unlike Argo cornstarch, this “superstarch” can maintain blood sugar levels for up to 7-8 hours overnight, allowing GSD patients and their families to get a full night of sleep. Still, after over 40 years, ingesting these starches remain the only approved therapy for blood glucose control in GSD patients.

How do people take their cornstarch doses?

Typically, people with GSD measure cornstarch doses in grams, mix it with water or a sugar-free beverage and drink it. Because the properties in cornstarch change if it’s heated, it must be taken in its raw form. Young children usually take cornstarch through a nasogastric (NG) tube and often have gastronomy tubes (g-tubes) placed, allowing direct access to their stomachs. Using a g-tube also allows for overnight doses to be administered by a parent, without waking a child to drink it.

What type of diet do people with GSD3 follow?

It is critical for individuals with GSD3 to avoid eating excess sugar and carbohydrate to ensure it is not stored in their liver and muscle cells. A typical meal will include fewer than 5 grams of sugar and fewer than 10-15 g of carbohydrates. To put this in perspective, a banana has 14 grams of sugar and 27 grams of carbohydrates, and 2 oz of pasta contains a whopping 42 grams of carbohydrates.

Additionally, people with GSD3 are treated with a very high protein diet including 3-4 grams of protein per kilograms of body weight. For a 50 pound child, this would be 70-90 grams of protein per day which can be difficult to maintain. Low-carb protein drinks and protein powder often supplement the diet for GSD3 patients.

What is most challenging about living with GSD3?

The dietary restrictions can be particularly hard for children, who can’t fully partake in events and celebrations that include food - such as birthday cake at a friend’s party, an apple during a school apple picking trip, or popsicles on a hot day at camp.

But more critical, is that treatment is required around the clock. Whether day or night, at school, work or home, cornstarch doses must be administered on time for survival. Other elements - exercise, exertion, hot or cold days, and illness - can also affect the efficacy of measured cornstarch doses, requiring constant management and modification.

Given the muscle involvement in type 3 GSD, physical exertion and activity must be carefully monitored to avoid undue stress and muscle damage. Daily blood sugar monitoring must be completed with finger pricks or with continuous glucose monitoring devices to catch potential low readings.

How does The GSD3 Foundation support patients with GSD?

100% of all funds raised by The GSD3 Foundation directly support GSD3 research for improved treatments and a cure. All work supported by The GSD3 Foundation is reviewed by our Scientific Advisory Board composed of some of the world’s leading experts in the field.

Is my donation to The GSD3 Foundation tax deductible?

Yes! The GSD3 Foundation is recognized by the IRS as a 501(c)(3) non-profit charity. Its tax ID number is 85-0667372.