Genetic Storage Diseases I

Question 1

What are the genetic basis for all glycogen storage diseases?

Answer 1

These are all autosomal recessive except for GSD VI (Liver phosphorylase X-Linked)

Question 2

Type I Glycogen Storage Disease AKA Von Gierkes disease is a defect in what enzyme and the build up of what precursor?

Answer 2

Defect in the hepatic Glucose-6-phosphatase or glucose 6-phosphate translocase.

Causes an accumulation of glucose within the liver and kidney. Presents with hypoglycemia and hepatomegaly.

Question 3

Type III Glycogen storage disease (Cori Disease) is a defect in what enzyme and the build up of what precursor?

Answer 3

Deficiency of debranching enzyme *Cannot break down glycogen.
Presents with hepatomegaly and hypoglycemia, short stature, and myopathy.

Question 4

Type V Glycogen storage disease “McArdle Disease” is caused by a defect in what enzyme and the build up of what precursor?

Answer 4

Lack of muscle phosphorylase limiting ATP generation and resulting in glycogen accumulation.

Presents with exercise intolerance with muscle cramps etc.

Question 5

Diagnosis of McArdle Disease can be done by what blood products?

Answer 5

Serum creatine kinase and failure to produce lactate with elevated glycogen and reduced phosphorylase activity.

Question 6

Type II Glycogen storage disease “Pompes Disease” is caused by a deficiency in what enzyme and a build up of what precursors?

Answer 6

Deficiency of Acid-Alpha-1,4 glucosidase (Acid maltase) causing an accumulation of glycogen in the heart, muscle, liver, and CNS.

Question 7

What are the symptoms of pompes disease?

Answer 7

Cardiomegally!!!!

Hypotonia, death prior to 2 years