Symptoms
The most common symptoms of GSDs include:
- Low blood sugar
- Enlarged liver
- Slow growth
- Muscle cramps
Signs and symptoms of specific types of GSDs include:
Type I:
- Large and fatty liver and kidneys
- Low blood sugar
- High levels of lactate, fats, and uric acid in the blood
- Impaired growth and delayed puberty
- Osteoporosis
- Increased mouth ulcers and infection
Type II:
- Enlarged liver and heart
- In severe cases, muscle weakness and heart problems develop.
- In severe cases, infants may suffer fatal heart failure by the age of 18 months.
- Milder forms of type II may not cause heart problems.
Enlarged Liver
Type III:
- Swollen abdomen due to an enlarged liver
- Growth delay during childhood
- Low blood sugar
- Elevated fat levels in blood
- Possible muscle weakness
Type IV:
- Growth delay in childhood
- Enlarged liver
- Progressive cirrhosis of the liver (which may lead to liver failure)
- May affect muscles and heart in late-onset type
Type V:
- Muscle cramps during exercise
- Extreme fatigue after exercise
- Burgundy-colored urine after exercise
Type VI, IX:
- Liver enlargement occurs, but diminishes with age
- Low blood sugar
Type VII:
- Muscle cramps with exercise
- Anemia
Diagnosis
The doctor will ask about symptoms and medical history. A physical exam will be done. Diagnosis of GSDs usually occurs in infancy or childhood. It is often done by the symptoms listed above. Tests may include:
- Biopsy of the affected organs
- Blood and urine samples
- MRI scan —a test that uses magnetic waves to make pictures of the inside of the body
Pre-implantation Genetic Diagnosis
This test may be used for an early diagnosis on some types of GSD. It is often done when there is a family history.
In this technique eggs and sperm are harvested from a couple who have a known risk. The egg is fertilized in the lab. The GSD free embryo is then implanted within the mother’s uterus. This technique allows parents to have additional unaffected children. This process may still pose ethical or religious concerns for some couples.