Glycogen Storage Diseases

Question 1

An autosomal recessive defect whereby patients present with hypoglycemia and ketosis, to the extent of seizures after overnight fasts

Answer 1

Glycogen Synthase Deficiency (Type 0)

Question 2

Patients with glycogen synthase deficiency will show a post-prandial

Answer 2

Hyperglycemia

Question 3

With significant reduction in liver glycogen stores, duing a fasting state the glycogen synthase deficient patient must rely more fully upon

Answer 3

Gluconeogenesis

Question 4

The abnormal glycogen structure that results from this autosomal recessive defect causes histopathologic alterations in the liver, evidenced at a very early age

Answer 4

Amylo-1,4 1,6-transglucosidase deficiency (Type IV; Amylopectosis; Andersen’s Disease)

Question 5

Patients with this disorder have glycogen that is produced only in abnormally long, linear polymers

Answer 5

Amylo-1,4 1,6-transglucosidase deficiency (Type IV; Amylopectosis; Andersen’s Disease)

Question 6

In Anderson’s disease, the cellular damage is likely due to the

Answer 6

Abnormally long glycogen

Question 7

A collection of genetic defects, the ultimate consequence of all of them being either the absence of or the inability to activate glycogen phosphorylase, resulting in an impairment of glycogenolysis

Answer 7

Liver Phosphorylase and Phosphorylase B kinase deficiencies (Types VI and VIII)

Question 8

In contrast to types VI and VII (above), patients with type V glycogen storage disease will experience exercise intolerance and muscle cramping if exercise is strenuous

Answer 8

Muscle Phosphorylase (Type V; McArdle’s Syndrome)

Question 9

Muscle involvement in these deficiencies is mild; patients typically suffer no significant motor impairments

Answer 9

Liver Phosphorylase and Phosphorylase B kinase deficiencies (Types VI and VIII)

Question 10

In patients with McArdle’s syndrome, energy requirements for mild and even moderate muscle activity can be satisfied by

Answer 10

Fatty Acid Oxidation

Question 11

What is most impaired in individuals with McArdle’s syndrome

Answer 11

Muscle “Burst”

Question 12

Patients present with both hepatomegaly and hypoglycemia

Answer 12

Amylo-1,6-glucosidase (debrancher) deficiency (Type III; Cori’s Disease)

Question 13

In patients with Type III; Cori’s disease, we will see an accumulation of so-called

Answer 13

Limit-dextrin

Question 14

Probably the most debilitating of the GSD’s, and regrettably also the most common

Answer 14

Glucose-6-phosphatase deficiency (Type I; von Gierke’s Disease)

Question 15

Presents with impairment of the final step in both glycogenolysis and gluconeogenesis, resulting in profound hypoglycemia during fasting periods

Answer 15

Glucose-6-phosphatase deficiency (Type I; von Gierke’s Disease)

Question 16

Patients with Glucose-6-phosphatase deficiency (Type I; von Gierke’s Disease) also show a significant

Answer 16

Lactic acidosis and hyperuricemia

Question 17

This enzyme is involved in lysosomal degradation of glycogen, and thus is not a participant in the energy balance dynamics of glycogen breakdown

Answer 17

a-Glucosidase

Question 18

Its responsibility is to digest (without harvesting energy) glycogen in lysosomal bodies

Answer 18

a-Glycosidase

Question 19

Deficiency of an enzyme which leads to accumulation of lysosomal glycogen and a variety of symptoms, including weakness, respiratory difficulties, and cardiac failure

Answer 19

Acid -Glucosidase deficiency (Type II, Pompe’s Disease)

Question 20

Deficiency for this enzyme presents similarly to that for muscle phosphorylase. Enzyme is also deficient in red blood cells, causing hemolysis

Answer 20

Phosphofructokinase deficiency (Type VII)

Question 21

Phosphofructokinase deficiency (Type VII) causes

Answer 21

Hemolysis