How is Glycogen Storage Disease diagnosed?
Individuals who have low blood sugars and large livers are at risk for one of the liver glycogenoses (type1a, 1b, 3, 6, 9, 11). Depending on the type of GSD they also have high levels of lactic acid, ketone bodies, uric acid and triglycerides in their blood. Diagnosis is confirmed with a gene test in the blood in most cases, in some cases fasting tests and or a liver biopsy might be additionally required.
What types of GSD are treated at BCCH and by whom?
Essentially all types of GSDs are treated at BCCH. Most of our patients have GSD type 1 a or 1b, and type 9. Patients are treated at BCCH until they are 18 years old and then graduated to the adult metabolic clinic at VGH (Vancouver General Hospital). We are also seeing patients with glycogenoses that affect the muscles mainly, like GSD2 (Pompe), 5 and 7.
At BCCH patients are seen by the biochemical genetics/metabolic disease team, which includes doctors, dietitians and nurses. All our doctors (Sylvia Stockler, Ramona Salvarinova, Gabriella Horvath) and the 3 dietitians (Keiko Ueda, Barbara Cheng, Alette Giezen) are seeing children. Dr. Horvath works both in the pediatric clinic at BCCH and in the adult metabolic clinic at VGH and sees patients with GSD after they have been graduated to the adult clinic together with the adult metabolic team. The VGH adult metabolic clinic specializes in adult metabolic medical care and also includes a team of doctors, dietitians and nurses lead by Dr. Sandra Sirs.
How do you get GSD?
GSD is a genetic condition. Most GSDs follow an autosomal recessive inheritance. Both males and females can be affected: only if both parents pass a defective gene to their child will the individual will be affected. Because parents usually only have one defective and one normal gene, they are healthy.
Isn't GSD similar to Diabetes?
In some way one could say that GSD is the opposite of diabetes. While in diabetes the blood sugar is too high, in GSD it is too low. There is however overlap, as some individuals with GSD may develop transiently very high blood sugars after intake of high glycemic carbohydrates. It is also known that patients particularly with GSD 1 may develop additional diabetes in adulthood. This is an extremely challenging situation, as both low and high blood sugars need to be managed.
How many GSD patients are being treated at BCCH? Are they all from BC?
Approximately 15 children with GSDs are currently treated at BCCH. They are all from BC.
How do you treat GSD?
Treatment depends on the type of the GSD, the severity and the individual characteristics of the affected patient. At BCCH for GSDs which cause low blood sugars we treat with cornstarch feedings during night and day. Some patients require tube feeding, particularly during night. Special diets are required for GSD 3 and 11. The BCCH based hematology team helps with the treatment of the neutropenia in GSD 1b patients with GCSF. GSD type 2 (Pompe disease) affects skeletal and heart muscle and is treated with enzyme replacement therapy.
Does BCCH collaborate with any doctors outside of BC? If so, who and in what regard?
We are collaborating with Dr. Weinstein (at Connecticut Childrens Medical Center). We are particularly interested in his cornstarch protocols and are grateful for all his advice he is providing for our most complicated patients.
Why do most children with GSD have a feeding tube?
A feeding tube is required if the child has a severe form of GSD (mostly GSD1) and is not able to maintain blood sugars with orally administered cornstarch. There are currently 2 different philosophies among the GSD specialists worldwide, those who preferentially use the feeding tube and those who preferentially use cornstarch via the natural oral route.
Will my child survive?
Yes, GSDs can effectively be treated.
Will my child be able to lead a normal life?
GSD is a lifelong condition. Lifelong treatment is necessary but many parts of life will be normal for the majority of affected individuals.
Q&A With Dr. Sylvia Stockler
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