What Is Glycogen Storage Disease Type III?
Glycogen Storage Disease Type III is also known as Cori disease, Forbes disease, limit dextrin disease, glycogen debranching enzyme deficiency disease. Is an autosomal recessive hereditary disease.
It is caused by mutations in a gene encoding a debranching enzyme (amyloglucosidase gene). Clinical presentations are diverse and depend on the tissues (muscle and/or liver) and enzyme activity involved. The disease has four subtypes A, B, C and D.
- GSD type III A is more common, with liver and muscle involvement.
- About 15% of patients with GSD type III B have only hepatic involvement without myopathy.
- Starch -1,6- glucosidase activity and oligomeric -1,4-1,4- glucanotransferase activity are selectively absent from the rare GSD Ⅲc forms and GSD Ⅲd forms.
What Is The Cause Of Glycogen Storage Disease Type III?
Glycogen Storage Disease Type III is an autosomal recessive disorder caused by mutations in a gene encoding a debranching enzyme (amyloglucosidase gene).
What Is The Symptoms Of Glycogen Storage Disease Type III?
What are the clinical manifestations of Glycogen Storage Disease Type III?
When glycogen debranching enzyme activity is deficient, a large amount of morphologically abnormal limit dextrins are caused to accumulate in the liver and/or muscle of the patient, causing various clinical symptoms manifested as hepatomegaly and hypoglycemia caused by liver disease in infancy and childhood.
- Ketoacidosis and growth retardation are also present, with occasional hyperlipidemia, hypotonia, muscle weakness, skeletal muscle atrophy, and cardiac involvement.
- Hepatomegaly and liver function usually improve with age, and normalization occurs in most cases after adolescence.
- Adenomas are occasionally seen, and some patients progress to cirrhosis.
- Cardiomyopathy with left ventricular hypertrophy is a common complication in childhood.
- Progressive muscle weakness and distal muscle atrophy are typical manifestation and in some cases are accompany by peripheral neuropathy in adults. Based on the clinical symptoms, it is difficult to confirm the diagnosis of this disease and there are many diseases that need to be identified.
Why does Glycogen Storage Disease Type III cause liver enlargement?
Glycogen decomposition or synthesis, because of enzyme defects will cause disorders, glycogen accumulation in hepatocytes, cause hepatomegaly. There are many illnesses.
How To Check For Glycogen Storage Disease Type III?
What tests are needed to diagnose Glycogen Storage Disease Type III？
Muscle and liver biopsy: Determination of glycogen content, glycogen morphology and glycogen debranching enzyme activity is an internationally accepted basis for diagnosis and classification.
Gene detection: AGL gene analysis can confirm the diagnosis, but it is costly and easy to miss diagnosis.
Liver function test: elevated serum transaminases in patients with liver disease. Serum creatine kinase concentrations were elevated in patients with muscle involvement. In addition there may be hypoglycemia, hyperlipidemia.
Electromyography: showing myopathic changes. Myopathic manifestations and neuropathy are more easily detected by electromyography and nerve conduction testing in older patients, and forearm muscle ischemia testing can be associated with abnormal increases in serum lactate concentrations.
Which illnesses are easily confused with Glycogen Storage Disease Type III?
Glycogen Storage Disease Type III is difficult to confirm in terms of clinical symptoms only and distinguish from other diseases causing liver and spleen enlargement.
How To Prevent Glycogen Storage Disease Type III?
Glycogen Storage Disease Type III currently has no effective preventive measures.
How To Treat Glycogen Storage Disease Type III?
Do patients with Glycogen Storage Disease Type III require inpatient care?
Clinical symptoms of Glycogen Storage Disease Type III are variable and can vary from mild to severe, requiring hospitalization for severe hypoglycemia, impaired liver function, liver cirrhosis, and severe muscle damage.
What are the treatment options for Glycogen Storage Disease Type III?
Treatment of primary disease: Glycogen Storage Disease Type III has no specific treatment method, and it is generally symptomatic treatment, for example, to avoid the occurrence of hypoglycemia. Frequent feeding of raw corn starch and continuous feeding of baby milk powder at night can help maintain blood glucose levels, and it is not necessary to avoid fructose and galactose in the diet. There is currently no good treatment for progressive myopathy and recombinant human acidic alpha-glucosidase is able to relieve glycogen levels in the muscle cells of our patient.
Management of complications: Continuous nasal feeding of glucose polymer and raw corn starch was ineffective, and liver transplantation was recommended in cases with significant cirrhosis or liver failure. Liver transplantation can improve blood glucose and other biochemical abnormalities as well as growth and development.
Can Glycogen Storage Disease Type III be cured?
Glycogen Storage Disease Type III is hereditary and cannot be cured in the traditional sense.
What Should Patients With Glycogen Storage Disease Type III Pay Attention To In Life?
What is the prognosis of Glycogen Storage Disease Type III?
In addition to muscular symptoms, other problems may improve with age.
After adolescence, liver size may retract to normal, but liver fibrosis may occur in some patients, and liver adenoma and its complications may occur in some patients.
Type B generally has a good prognosis, with no cirrhosis of the liver in adulthood, and Type A has a relatively poor prognosis, with myopathy and cardiomyopathy developing and aggravating after a considerable incubation period, most of which develop severe muscle limitation in the mid-40s.
Do patients with Glycogen Storage Disease Type III require frequent follow-up?
It is recommended that α -fetoprotein and liver ultrasound be performed annually to monitor liver adenomas.
Malignant transformation of hepatic adenomas is rare, and patients with myopathy should undergo periodic cardiac evaluation, including electrocardiograms and echocardiography.
Does Glycogen Storage Disease Type III affect fertility?
Some women with Glycogen Storage Disease Type III involvement may have polycystic ovaries but are still fertile.