What Is Glycogen Storage Disease?

Glycogen storage disease is a rare group of autosomal-associated recessive genetic diseases. Patients cannot metabolize glycogen normally, which hinders glycogen synthesis or decomposition. Therefore, glycogen (a starch) is deposited in a large amount in tissues. disease. There are many types of glycogen storage diseases, of which liver diseases are the main types of , , , and , and muscle tissue damage is the main type of , , and . The most serious glycogen storage disease is glycogen storage disease type II, which usually develops within one year of age. Avoiding exercise can make the symptoms subside. Muscle damage causes myosin to be released into the blood. Myosin is harmful to the kidneys. Restricting exercise can reduce myosin levels. Drink plenty of water, especially after exercise, to dilute myosin.

Basic Information

English name: glycogen storage disease
Visiting department: Endocrinology

Common causes: Autosomal recessive
Common symptoms: Hepatomegaly, hypoglycemia, muscle atrophy, hypotonia, dyskinesia, etc.

Causes of glycogen storage disease

Glycogen storage disease is an autosomal recessive inheritance, while the phosphorylase kinase-deficient type is an X-linked inheritance.

Clinical manifestations of glycogen storage disease

Glycogen storage disease is mainly manifested as hepatomegaly and hypoglycemia, including type Ia (glucose-6-phosphatase deficiency) and the more rare type Ib (G-6-P microsomal transferase deficiency), type III, and type VI Deficiency of phosphatase b kinase with recessive inheritance of X and autosomes. Muscle-energy dysfunction glycogen storage disease is mainly manifested as muscle atrophy, hypotonia, and dyskinesias, including type V, type , lack of phosphoglycerate mutase and lack of LDHM subunits, and type and type .

1. Type I glycogen storage disease

It is most common clinically and due to the lack of glucose-6-phosphatase, glucose 6-phosphate cannot be hydrolyzed to glucose. Main manifestations: Patients with severe hypoglycemia induced by fasting appear hypoglycemia, convulsions and coma after birth. Long-term hypoglycemia affects brain cell development, mental retardation, and death within 2 years; with ketosis and lactic acidosis ; Hyperlipidemia There are yellow tumors on the hips and extremities, concentric obesity, swollen abdomen, and a "baby" shape; hyperuricemia ; liver and renal tubular epithelial cells have a large amount of glycogen deposits that appear in the newborn Liver enlargement and kidney enlargement. When grown into an adult, single or multiple hepatic adenomas, progressive glomerulosclerosis, and renal failure may occur; Growth retardation forms a dwarf state.

2. Type II glycogen storage disease

Glycogen deposits are present throughout the body, especially infiltration and hypertrophy of myocardial glycogen. Infant type develops as early as 1 month after birth, rarely survives to 1 year old, looks like cretinism, has large tongue, cough, dyspnea, and died of heart and lung failure before 2 years old. Adolescent type is mainly manifested by progressive muscular dystrophy. Adult type manifests as skeletal muscle weakness.

3. Type III glycogen storage disease

Heap multi-branched glycogen, also known as boundary dextrin disease. Main manifestations: Hypoglycemia is milder than type I; Large liver can develop liver fibrosis and cirrhosis; Growth is delayed .

4. Type IV glycogen storage disease

Glycogen, which has few branches, is also called amylopectin. Liver is large, liver cirrhosis, growth disorders, low muscle tone, such as newborn cirrhosis should be excluded from this disease. Patients died of heart and liver failure more than 1 year of age.

5. Type glycogen storage disease

Due to the lack of phosphorylase, patients have high levels of glycogen in the muscles but little or no lactic acid in the blood after exercise. Many adolescents have symptoms, moderate exercise cannot be completed, small amounts of muscle activity are not restricted, muscles are fatigued, muscle spasms, and myosinuria is present.

6. Type VI glycogen storage disease

Mainly manifested as hepatomegaly, mild or no hypoglycemia.

7. Glycogen storage disease

Muscle pain and spasm after exercise, myosinuria, and mild non-spherical erythrocyte hemolytic anemia.

8. Phosphatase b kinase deficiency ( or type)

Hepatomegaly, occasionally fasting hypoglycemia, stunted growth, spontaneous relief during puberty.

9. Type X glycogen storage disease

Liver and muscle glycogen deposition, liver enlargement, fasting hypoglycemia muscle spasm, and a certain degree of mental retardation.

10. Type O is glycogen synthase deficiency

Patients often develop fasting hypoglycemia, hyperketones, muscle cramps, and some degree of mental retardation, which is easily confused with hypoglycemic ketosis.

Glycogen storage disease test

Laboratory inspection

Fasting blood glucose measurement; blood total cholesterol, triacylglycerol measurement; blood lactic acid measurement, uric acid measurement; glucagon test; liver function transaminase measurement.

2. Other auxiliary inspections

According to the condition should be selected for bone X-ray examination, abdominal B ultrasound, electrocardiogram, echocardiography and so on. A tissue or organ biopsy is performed if necessary.

Diagnosis of glycogen storage disease

1. Type I diagnosis basis

(1) Clinical manifestations: hepatomegaly, fasting hypoglycemia, short stature, and obesity.

(2) Blood biochemical examination: fasting blood glucose is low, blood triacylglycerol and cholesterol are increased, and blood lactic acid and uric acid are increased.

(3) Glucagon test Glucagon is injected intramuscularly, blood glucose is measured every 15 minutes for 2 hours, and normal people's fasting blood glucose can increase by 3 to 4 mmol / L after 10 to 20 minutes. Patients with this disease can increase by <0.1 mmol / L 2 Blood sugar did not rise within hours, lactic acid increased by 3 to 6 mmol / L, and the existing lactic acidosis was aggravated, and blood pH decreased.

(4) Liver aspiration biopsy is based on the diagnosis of the disease. The liver glycogen of patients is usually more than 6%, the glucose-6-phosphatase activity is reduced or even lost, and a large amount of glycogen is deposited in the nucleus.

(5) Conversion of fructose or galactose to glucose test Rapid intravenous infusion of a 25% solution prepared with fructose or galactose, taking blood once every 10 minutes for a total of 1 hour, measuring blood glucose, lactose, fructose, galactose content, blood Glucose does not rise, while lactic acid rises significantly.

(6) X-ray examination of bones showed delayed callus and osteoporosis.

2. Type II diagnosis basis

(1) Symptoms and signs Patients with poor growth and development, cardiac hypertrophy, and muscle relaxation.

(2) Creatine phosphatase and aldolase Creatine phosphatase and aldolase are increased.

(3) The diagnosis was confirmed by muscle and liver biopsy. Electron microscopy showed the deposition of glycogen particles, lack of 14-glucosidase, and skin biopsy fibroblast culture did not exist.

(4) Glycogen particles can be seen in amniotic fluid cells of early pregnancy .

3. Type III diagnosis basis

(1) Symptoms and signs of liver enlargement and muscle weakness.

(2) Glucagon test. After fasting intramuscular injection in the morning, the patient's blood glucose does not rise or rises very little. After intramuscular injection 2 hours after eating, the blood glucose can increase by 3 to 4mmol / L, and the blood lactic acid concentration remains unchanged.

(3) A purple response to iodine measurements on liver or muscle biopsy confirmed the presence of bound dextrin. Can also be used for red blood cells and white blood cells with iodine detection.

(4) Determination of 1,6-glucosidase activity of red blood cells and white blood cells

4. Type IV diagnosis basis

The patient had cirrhosis, hepatosplenomegaly, jaundice, and ascites. Hepatic tissue iodine test showed a purple starch positive response.

5. Type diagnosis basis

(1) Symptoms and signs Restricted muscle activity, muscle spasms, etc.

(2) Patients with beam-arm exercise test tying the upper arm's blood pressure band, inflating the pressure of the air band to the systolic blood pressure to block the blood flow, and then let the patient stretch the fingers to exercise repeatedly for 1 minute. Lactic acid increased after exercise, but the patient's blood lactic acid did not increase.

(3) Muscle biopsy showed muscle glycogen accumulation and muscle phosphorylase deficiency.

6. Type diagnosis basis

(1) Symptoms and signs of liver are large, and hypoglycemia may occur.

(2) Glucagon injection on an empty stomach or after a meal cannot raise blood sugar.

(3) Liver biopsy has high glycogen content and low phosphorylase activity. This enzyme is low in leukocytes.

7. Basis of diagnosis

(1) The symptoms and signs are the same as type V.

(2) Lack of phosphofructokinase in muscle biopsy , low activity of this enzyme in red blood cells.

8. Lack of diagnostic evidence for phosphatase b kinase

Symptoms and signs such as hepatomegaly, etc .; Detect the decrease of leukocyte or liver cell enzyme activity.

9.X-type diagnosis basis

hepatomegaly; glucagon test positive; liver or muscle biopsy.

10.O-type diagnosis basis

Symptoms and signs; Glucagon test; Postprandial liver biopsy, liver glycogen content is less than 0.5% of wet liver weight; Glycogen synthase activity of red blood cells.

Glycogen Storage Disease Treatment

Introduce parents to the knowledge and prognosis of the disease, and teach parents about the importance of diet in order to control the disease. Since the application of diet therapy, many patients have achieved normal growth and development after long-term treatment. Even after stopping treatment in adulthood, symptoms such as hypoglycemia no longer occur. Teach parents how to observe the signs and treatment of hypoglycemia, emphasize prevention of infection and exercise The necessity of the body needs to be reviewed on an outpatient basis and regularly followed up.

1. Type I

(1) Prevention and treatment of acute onset of hypoglycemia . Intravenous injection of 25% glucose immediately to maintain blood glucose between 2.22 and 6.66 mmol / L. Take a high-protein, low-fat diet every 2 to 3 hours.

(2) Prevention and treatment of acidosis , high blood lactic acid, should take sodium bicarbonate.

(3) Prevention of infection

(4) Allopurinol (Allopurinol) for the treatment of hyperuricemia.

2. Type II

There is no effective treatment.

3. Type III

Eat a small number of meals, high-protein diet to limit fat and total calories to prevent hypoglycemia.

4. Type V

Avoid fatigue and strenuous exercise; Prepare glucose or fructose or give isoproterenol before exercise.

5.Type VI

Should be high-protein diet, a small number of meals to prevent hypoglycemia.