Question 1: What is glycogen? What is glycogen accumulation disease?
As we know, the nutrients required by the human body for life activities include: carbohydrates, fats, proteins, vitamins, minerals, water, dietary fiber, etc. However, only three kinds of energy are provided by the body: carbohydrates, fats and proteins, which are referred to as the “three energy supplying nutrients”. Under normal circumstances, the proportion of energy provided by each energy-supplying nutrient in the total energy demand of the body is different, among which, carbohydrates provide the most energy, accounting for about 50-55% of the total demand of the body; fat is the second, accounting for about 25-30%; and finally protein, accounting for about 10%-15%.
Therefore, carbohydrates are the most important source of energy for the human body. Carbohydrates (such as rice, pasta, fruit, etc.) eaten by people can only be absorbed after digestion in the gastrointestinal tract and transformed into glucose, which raises blood sugar in the body and provides energy to maintain the body’s functions and growth and development. Blood sugar in the body must be maintained in a normal range, not too high and not too low. When there is an excess of sugar substances in the body, the body will store the glucose that cannot be used for a while, and many glucose molecules gather together and become glycogen.
The glycogen stored in the liver is called hepatic glycogen, and the glycogen stored in the muscles is called myoglycogen. Hepatic glycogen is the body’s main storehouse of glycogen and the most important source of blood sugar. When the body is not eating, the glycogen stored in the liver releases glucose to maintain normal blood glucose levels in the body and to ensure that hypoglycemia does not occur. The release of glucose from the liver requires the participation of many enzymes to complete this series of biochemical processes.
Glycogen storage disease (GSD) is a disorder of glycogen metabolism in the body caused by a deficiency of one of the enzymes involved in glycogen metabolism. The incidence of glycogen storage disease is about 1/20,000~1/25,000 in Europe and the United States, and the clinical manifestations are diverse due to different types of enzyme deficiencies. According to the clinical manifestations and biochemical characteristics, there are thirteen types, among which type I GSD is the most common.
There are at least 8 types of enzymes necessary for glycogen synthesis and catabolism, and there are 12 subtypes of clinical diseases caused by these enzyme defects. Among them, type I, III, IV, VI, and IX glycogen accumulation diseases are mainly liver lesions; type II, V, and VII glycogen accumulation diseases are mainly muscle tissue damage.
Take the most common type I glycogen accumulation disease as an example, due to the lack of glucose-6-phosphatase in the liver, glycogen cannot release glucose, and more and more glycogen exists in the liver, and the liver becomes bigger and bigger, while symptoms of hypoglycemia appear. Common manifestations such as: children will then always cry out for hunger (physiological feedback due to low blood sugar), big belly (enlarged liver), not growing (low blood sugar, insufficient energy supply), easy nosebleeds (liver function damage, blood clotting disorder), anemia and other symptoms.
Long-term hypoglycemia will cause a series of metabolic disorders in the organism, such as.
(1) Increase of lactic acid in blood and acidosis;
(2) Elevated blood lipids, resulting in yellow tumors (lipomas) on the hips and extremities, centripetal obesity, abdominal bulging, and a “doll” body shape, etc;
(3) Elevated uric acid, leading to gout and hand and foot deformities;
(4) Hepatomegaly and liver damage, elevated transaminases, liver adenomas, etc.
Without treatment, many complications can occur in children with the disease, leading to death in severe cases.
Question 2: Why does a child have glycogen accumulation disease when both parents are normal?
Glycogen accumulation disease is a congenital genetic disorder that is mainly inherited in an autosomal recessive manner. In other words, the mother and father each have “1” mutation in the gene that causes the disease, and their appearance does not show, and they look like normal people, which is often referred to as “carriers” of the gene that causes the disease. However, when both parents pass the mutation to their child, the child carries “2” mutations in the gene and becomes sick and becomes a glycogen accumulation disease patient.
Question 3: Is there a cure for glycogen accumulation disease?
Glycogen accumulation disease is a genetic metabolic disease caused by gene mutations, and there is no cure for it. In recent years, enzyme replacement therapy has been developed for some subtypes, i.e. the enzymes are supplemented with whatever enzymes the child lacks, such as glycogen accumulation disease type II (Pompe disease). It is difficult for the average family to afford.
Most of the treatment of glycogen accumulation disease manifested by hypoglycemia can be a combination of high protein, high glucose diet with multiple feedings, supplemented with raw corn starch at regular meal intervals to maintain normal blood glucose levels. Comprehensive dietary therapy cannot cure the disease, but it can greatly improve the clinical symptoms of the child, improve the quality of life, and reduce the rate of death and disability due to complications, but comprehensive dietary therapy must be adhered to for life.
Question 4: What are the dietary considerations for children with glycogen accumulation disease?
1, a small number of meals, diet based on rice and flour and other food, can be supplemented with vegetables and meat, but should not eat too much at a time, to control blood sugar at the level of the main meal;
2, should not eat too sweet food, should not drink sugary drinks, because these foods and drinks, the ingredients are mainly free glucose, after eating, blood sugar rises quickly, but also falls quickly, can not play a role in maintaining blood sugar levels;
3. For children with high blood uric acid, they should not eat foods with high purine content, such as seafood, animal offal, meat soup, etc.; adults should abstain from alcohol and drink more water at the same time. Children with stones in the urine should pay attention to a low salt and light diet and drink more water, which can dilute the concentration of uric acid in the blood and flush the urethra to speed up the discharge of uric acid and urethral stones in the blood.
Question 5: Why does glycogen accumulation disease require regular follow-up?
1. Glycogen accumulation disease is a rare and complex genetic disease that affects multiple organs and systems, with varying degrees of severity and life-threatening clinical manifestations;
2. After the last treatment, doctors need to monitor and evaluate the effect of the treatment regularly and adopt treatment plans to improve the efficacy;
3. As the child grows older, some other comorbidities of glycogen accumulation disease will become apparent, such as gout due to hyperuricemia, hepatic adenoma, and physical growth retardation, etc., which need to be detected and treated in a timely manner.