Von Gierke’s and McArdle’s disease are two of the most common glycogen storage diseases.Which of the following statements are TRUE for these diseases? i) Von Gierke’s disease typically results from a mutation in glucose 6-phosphatase.ii) McArdle’s disease typically results from a mutation in glycogen phosphorylase.iii) McArdle’s disease typically results from a mutation in glucose 6-phosphatase.iv) Von Gierke’s disease typically results from a mutation in glycogen phosphorylase.v) Von Gierke’s disease patients cannot release glucose to the blood, have enlarged livers and kidneys and elevated lipids in the blood (hyperlipidaemia).vi) McArdle’s disease patients cannot release glucose to the blood, have enlarged livers and kidneys and elevated lipids in the blood (hyperlipidaemia).vii) McArdle’s disease patients suffer from severe muscle cramps with initial attempts of exercise, but these cramps subside with repeated attempts.viii) Von Gierke’s disease patients suffer from severe muscle cramps with initial attempts of exercise, but these cramps subside with repeated attempts.
Question
Von Gierke’s and McArdle’s disease are two of the most common glycogen storage diseases.Which of the following statements are TRUE for these diseases? i) Von Gierke’s disease typically results from a mutation in glucose 6-phosphatase.ii) McArdle’s disease typically results from a mutation in glycogen phosphorylase.iii) McArdle’s disease typically results from a mutation in glucose 6-phosphatase.iv) Von Gierke’s disease typically results from a mutation in glycogen phosphorylase.v) Von Gierke’s disease patients cannot release glucose to the blood, have enlarged livers and kidneys and elevated lipids in the blood (hyperlipidaemia).vi) McArdle’s disease patients cannot release glucose to the blood, have enlarged livers and kidneys and elevated lipids in the blood (hyperlipidaemia).vii) McArdle’s disease patients suffer from severe muscle cramps with initial attempts of exercise, but these cramps subside with repeated attempts.viii) Von Gierke’s disease patients suffer from severe muscle cramps with initial attempts of exercise, but these cramps subside with repeated attempts.
Solution
The following statements are true for Von Gierke’s and McArdle’s diseases:
i) Von Gierke’s disease typically results from a mutation in glucose 6-phosphatase. This is true. Von Gierke's disease, also known as glycogen storage disease type I, is caused by a deficiency in the enzyme glucose-6-phosphatase, which is crucial for the final step of gluconeogenesis and glycogenolysis.
ii) McArdle’s disease typically results from a mutation in glycogen phosphorylase. This is true. McArdle's disease, also known as glycogen storage disease type V, is caused by a deficiency in the enzyme muscle glycogen phosphorylase. This enzyme is needed for the breakdown of glycogen in muscle cells.
v) Von Gierke’s disease patients cannot release glucose to the blood, have enlarged livers and kidneys and elevated lipids in the blood (hyperlipidaemia). This is true. The inability to release glucose from the liver results in hypoglycemia. The accumulation of glycogen in certain organs and tissues, especially the liver and kidneys, can cause these organs to enlarge and can affect their function. Hyperlipidemia occurs as a result of the increased synthesis of fatty acids and triglycerides in the liver.
vii) McArdle’s disease patients suffer from severe muscle cramps with initial attempts of exercise, but these cramps subside with repeated attempts. This is true. This phenomenon is known as the "second wind" phenomenon. It is due to the mobilization of other energy sources in muscle, such as fatty acids, and the dilation of blood vessels to increase blood flow and oxygen supply to the muscles.
The other statements are false. McArdle’s disease does not result from a mutation in glucose 6-phosphatase (iii), Von Gierke’s disease does not result from a mutation in glycogen phosphorylase (iv), McArdle’s disease patients do not typically have enlarged livers and kidneys and elevated lipids in the blood (vi), and Von Gierke’s disease patients do not typically experience severe muscle cramps with initial attempts of exercise that subside with repeated attempts (viii).
Similar Questions
Glycogen storage disease type I (GSD I) or von Gierke's disease, is the most common of the glycogen storage diseases. This genetic disease results from deficiency of the enzyme glucose-6-phosphatase.The metabolic outcomes of GSD I are likely to include :Group of answer choicesHigh blood glucose, decreased blood pH, decreased glycogen storage in liver and kidneysLow blood glucose, increased blood pH, decreased glycogen storage in liver and kidneysHigh blood glucose, increased blood pH, increased glycogen storage in liver and kidneysHigh blood glucose, decreased blood pH, increased glycogen storage in liver and kidneysLow blood glucose, increased blood pH, increased glycogen storage in liver and kidneysLow blood glucose, decreased blood pH, decreased glycogen storage in liver and kidneysHigh blood glucose, increased blood pH, decreased glycogen storage in liver and kidneysLow blood glucose, decreased blood pH, increased glycogen storage in liver and kidneys
describe the various types of glycogen storage diseases.
The liver plays a central role in maintaining blood glucose homeostasis. It contains the highest concentration of glycogen of any organ in the body and is one of the few organs that can regenerate glucose from metabolic byproducts. The liver can replenish glucose in muscle and brain tissue during times of fasting, and it can help prevent lactate accumulation during intense physical activity.Von Gierke disease is a rare autosomal recessive disorder that arises from inactivating mutations in the liver enzyme glucose 6-phosphatase (G6Pase). It affects roughly 1 in 100,000 individuals, and the resulting loss of enzymatic activity leads to hypoglycemia (low blood sugar) that cannot be counteracted by catabolic hormones like glucagon. Von Gierke can also cause an increase in blood acidity concurrent with lactate build-up. Patients typically become symptomatic shortly after birth with convulsions, hyperventilation, and tremors. Left untreated, patients may develop gout, osteoporosis, and life-threatening complications such as kidney failure and liver tumors.In an effort to examine the biochemical consequences of this disorder, scientists generated a genetically engineered mouse model with liver G6Pase expression under the control of the Tet-Off system at both alleles. Under this system, addition of the small molecule tetracycline in the water source of the mouse rapidly shuts off G6Pase gene expression and therefore can recapitulate von Gierke disease. Blood glucose and pH levels were measured daily in two groups of genetically engineered mice over 20 days: group A mice received no tetracycline and group B mice were given tetracycline starting at day 10. All mice were fed identical low-sugar diets throughout the experiment.Adapted from Froissart R, Piraud M, Boudjemline AM, et al. Glucose-6-phosphatase deficiency. Orphanet J Rare Dis. 2011;6:27. Question 7Treatment with which of the following could help counteract hypoglycemia in patients with von Gierke disease?A.InsulinB.Vitamin AC.EpinephrineD.Starch
Which of the following abnormalities will prevent glycogen synthesis?Group of answer choicesA. A glycogenin that contains no tyrosine residues in its primary structureB. A glycogenin that has no glycosyl transferase activityC. A glycogenin that is unable to bind UDP-GlucoseD. A glycogenin that is unable to create branches in linear glucose chainsE. More than one choice above
Glycogen storage disease type VII or Tauri’s disease, results from deficiency of the enzyme phosphofructokinase-1 (PFK-1) in muscle. The metabolic outcomes in muscle cells are likely to include blocked glycolysis and:Group of answer choiceslow [ATP], accumulation of glycogen, downregulation of oxidative phosphorylation.low [ATP], accumulation of glycogen, upregulation of oxidative phosphorylation.high [ATP], depletion of glycogen, upregulation of oxidative phosphorylation.high [ATP], accumulation of glycogen, downregulation of oxidative phosphorylation.low [ATP], depletion of glycogen, upregulation of oxidative phosphorylation.high [ATP], depletion of glycogen, downregulation of oxidative phosphorylation.low [ATP], depletion of glycogen, downregulation of oxidative phosphorylation.high [ATP], accumulation of glycogen, upregulation of oxidative phosphorylation.
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