Von Gierke diseaseDefinition: Von Gierke disease is a group of inherited metabolic disorders�that involve increased glycogen storage. Since glycogen is needed to fuel muscles, problems with its metabolism can affect the whole body. Some problems include slow growth, enlarged liver, gout, kidney failure, and chronic low blood sugar. In the past, von Gierke disease was associated with stunted growth, delayed or absent puberty, and early death. With the development of treatments, growth, puberty, and quality of life have markedly improved for those with von Gierke disease.
Alternative Names: Type I glycogen storage disease
Causes, incidence, and risk factors: All type I glycogen storage diseases are inherited in an autosomal recessive manner. Autosomal chromosomes are the non-sex chromosomes. If both parents are carriers of the mutated gene, each of their children has a 25% chance of inheriting the disease. All the subtypes of this disease share a common feature -- lack of proteins responsible for transporting or breaking down the components of glycogen. As a result, abnormal amounts of glycogen accumulate in various tissues, causing a wide range of symptoms.
Symptoms: - Severe low blood sugar (hypoglycemia)
- Doll-like features in children, including puffy cheeks, a thin chest and limbs, and protuberant belly
- Intolerance of fasting, need for frequent feeding
- Stunted growth
- Delayed or underdeveloped puberty
- Enlarged liver
- Gout (a painful inflammation of joints)
- Easy bruising, nosebleeds
- Increased risk for infection and ulcers of the mouth or bowels, due to malfunctioning white blood cells (in one type of the disease)
Signs and tests: - Enlarged liver with accumulated glycogen and fat on exam
- Liver tumors (adenomas)
- Low blood sugar (hypoglycemia)
- High blood uric acid (a risk factor for gout)
- High blood lactic acid
- Increase in blood lactic acid and failure to increase blood sugar when adrenaline or glucagon are administered
- High blood fats, especially triglycerides
- Inability to tolerate fasting
- Improvement in response to frequent feedings
- Kidney stones or kidney failure
- Biopsy of liver or kidney showing accumulated glycogen
- Enzyme tests on liver biopsy
- Genetic tests for mutations
Treatment: Treatment for this disease concentrates on avoiding low blood sugar. Frequent feedings are needed during the day, especially foods that contain carbohydrates (starches). Neither fruit nor milk sugar can be adequately broken down in this disease, and are best avoided. Overnight fasting is avoided by continuous feedings (through a tube that goes through the nose into the stomach) of sugars or uncooked cornstarch. The tube can be put in at bedtime and taken out each morning. A medication called allopurinol, which can lower blood uric acid and decrease the risk for gout, is often used.
Support Groups: Association for Glycogen Storage Disease, www.agsdus.org.
Expectations (prognosis): Since development of the treatments listed above, patients have improved growth, development and health. Those who are identified and carefully treated at a young age can live into adulthood. Early treatment also decreases the rate of severe problems such as liver tumors, kidney failure, gout and life-threatening low blood sugar that can occur without treatment.
Complications: - Seizures, lethargy, confusion due to low blood sugar
- Gout
- Kidney failure
- Liver tumors
- Short adult stature
- Underdeveloped secondary sexual characteristics
- Osteoporosis
- Ulcers of the mouth or bowel
- Frequent infection
Calling your health care provider: Call your health care provider if there is a family history of glycogen storage disease or early infant death due to low blood sugar. Genetic counseling is recommended if there is a family history of glycogen storage disease.
Prevention: There is no simple way to prevent glycogen storage disease. Prospective parents may seek genetic counseling and testing to determine their risk for passing on von Gierke disease. Treatment is effective at preventing many of the complications.
|
