Glycogen Storage diseases

Question 1

Von Gierke Disease (Type I) - findings

Answer 1

severe tasing hypoglycemia
marked increase glycogen in liver and kidneys
increase blood lactate
increase triglycerides
increase uric acid (gout)
hepatomegaly, renomegaly
*liver does not regulate blood glucose

Question 2

Von Gierke Disease (Type I) - deficient enzyme

Answer 2

glucose-6-phosphatase (completes gluconeogenesis and glycogenolysis)
ASHKENAZI JEW

Question 3

Von Gierke Disease (Type I) - comments

Answer 3

treatment: frequent oral glucose/cornstarch; avoidance of fructose and galactose
impaired gluconeogenesis and glycogenolysis

Question 4

Pompe disease (type II) - findings

Answer 4

cardiomegaly
hypertrophic cardiomyopathy
hypotonia
exercise intolerance
systemic findings lead to early death (failure to thrive)

Question 5

Pompe disease (type II) - deficient enzyme

Answer 5

lysosomal acid α-1,4-glucosidase w/ α-1,6-glucosidase activity (acid maltase)
degrades glycogen to glucose in lysosomes

Question 6

Pompe disease (type II) - comments

Answer 6

Pompe trashes the pumps (heart, liver, muscle)
no pain
macroglossia, hepatomegaly

Question 7

Cori disease (type III) - findings

Answer 7

milder form of Von Gierke (type I) with normal blood lactate levels
accumulation of limit dextrin-like structures in cytosol

Question 8

Cori disease (type III) - deficient enzyme

Answer 8

debranching enzyme (α-1,6-glucosidase)
breakdown of glycogen and glucose mobilization from liver and muscle

Question 9

Cori disease (type III) - comments

Answer 9

GLUCONEOGENESIS IN TACT

fasting hypoglycemia, hepatomegaly

Question 10

McArdle disease (type IV) - findings

Answer 10

increase glycogen in muscle, but muscle cannot break down -> painful muscle cramps, myoglobulinuria (red urine) w/ strenuous exercise, and arrhythmia from electrolyte abnormalities
second-wind phenomenon during exercise d/t increase muscular blood flow

Question 11

McArdle disease (Type IV) - deficient enzyme

Answer 11

skeletal muscle glycogen phosphorylase (myophosphorylase)

hall mark is flat venous lactate curve with normal rise in ammonia levels during exercise

Question 12

McArdle disease (type IV) - comments

Answer 12

blood glucose levels typically unaffected