Biochem June 25 Flashcards
Inheritance of glycogen storage diseases I-IV?
autosomal recessive
what is glycogen storage disease I?
Von Gierke disease
what is glycogen storage disease II?
Pompe Disease
what is glycogen storage disease III?
Cori disease
what is glycogen storage disease IV?
McArdle
Which enzyme is deficient in Von Gierke Disease?
Glucose 6 Phosphatase
Lab findings in Von Gierke Disease
Severe fasting hypoglycemia (cant complete glycogenolysis or gluconeogenesis
-Increased glycogen in liver/kidneys, high blood lactate, high triglycerides, high uric acid, hepatomegaly and renomegaly
Why does lactic acidosis occur with Von Gierkes diseasE?
the cori cycle requires G6P which cannot be produced, leading to lactate build up
what pathways are impaired in von gierkes?
Gluconeogensis, glycogenolysis, consequently cori cycle
how to treat Von gierkes
frequent oral glucose/cornstarch
AVOID fructose/galactose which feed into glycolysis
what is deficient in Pompe disease?
Lysosomal acid alpha-1-4-glucosidase
can gluconeogenesis be performed in pompe disease?
yes - its just muscle glycogenolysis that is impaired
clinical manifestions of pompe disease
Cardiomegaly, hypertrophic cardiomyopathy, hypotonia, excercise intolerance, early death
what accumulates in pompe disease (type II) ?
glycogen accumulates in lysosomes
What enzyme is deficient in cori disease?
debranching enzyme (alpha 1,6 glucosidase)
Findings in cori disease
mild hypoglycemia (milder form of von gierkes)
- normal blood lactate
- accumulation of limit dextrin-like structures in cytoplasm
does cori disease (type III) have intact gluconeogenesis?
yes
Which organs are primarily effected in cori disease?
Muscles
-may lead to cardiomyopathy
What is deficient in McArdle disease?
Skeletal muscle glycogen phosphorylase
Lab finding hallmark of mcardle disease?
FLAT venous lactate curve with normal rise in ammonia levels during exercise
Presentation of McArdle disease
Painful muscle cramps, myoglobinuria with strenous exercise, and arythmia from electrolyte abnormalities
Second wind phenomonen due to increased muscular blood flow
Which organs are primarily effect in mcardle disaese?
muscles - glycogen builds up but muscles cannot break it down
Does mcardle disease have intact gluconeogenesis?
yes
What is type 0 glycogen storage disease?
Glycogen synthase deficiency, resulting in no glycogen and thus hypoglycemia but no hepatomegaly
