Findings (GSD)
This GSD involves painful muscle cramps, myoglobinuria with strenuous exercise, and arrhythmia from electrolyte imbalances. The "second-wind" phenomenon is noted during exercise.
McArdle disease (type V)
This sphingolipidosis presents in infancy with progressive neurodegeneration, developmental delay, hyperreflexia, hyperacusis (normal sounds are painfully loud), "cherry-red" spot on macula, lysosomes with onion skin, and NO hepatomegaly.
Tay-Sachs disease
Enzyme deficiency in Von Gierke's (type I)
Glucose-6-phosphatase
Enzyme deficiency in Tay-Sachs
Hexosaminidase A
These three lysosomal storage diseases are more common in Ashkenazi Jews
Tay-Sachs, Niemann-Pick, Gaucher
Cardiomegaly, hypertrophic cardiomyopathy, hypotonia, exercise intolerance, and systemic findings lead to early death in this GSD.
Pompe disease (type II)
This sphingolipidosis is the most common LSD. It presents with hepatosplenomegaly, pancytopenia, osteoporosis, avascular necrosis of the femur, bone crises, and lipid-laden macrophages resembling crumpled tissue paper.
Gaucher disease
Enzyme deficiency in Pompe disease (type II)
Lysosomal acid alpha-1,4-glucosidase (acid maltase)
Enzyme deficiency in Gaucher's disease
Glucocerebrosidase
These two lysosomal storage diseases are treatable with recombinant enzyme replacement
Fabry disease and Gaucher disease
This GSD presents as a milder form of von Gierke (type I) with normal blood lactate levels as gluconeogenesis remains intact.
Cori disease (type III)
This LSD is a sphingolipidosis that presents with progressive neurodegeneration, foam cells, a cherry-red spot on the macula, and hepatosplenomegaly.
Niemann-Pick disease
Debranching enzyme (alpha-1,6-glucosidase)
Enzyme deficiency in Fabry disease
Alpha-2-galactosidase A
This is the #1 cause of death in Pompe disease
Heart failure
This GSD presents with severe fasting hypoglycemia, increased glycogen storage in the liver and kidneys, along with increased blood lactate, triglycerides, and uric acid. Hepatomegaly and renomegaly are common. Gluconeogenesis and glycogenolysis are impaired.
This sphingolipidosis presents early with a triad of episodic peripheral neuropathy, angiokeratomas, and hypohidrosis. Later it also involves progressive renal failure and cardiovascular disease.
Fabry disease
Enzyme deficiency in McArdle disease (type V)
Skeletal muscle glycogen phosphorylase (Myophosphorylase)
Enzyme deficiency in Niemann-Pick disease
Sphingomyelinase
This is the treatment for Von Gierke disease
Oral cornstarch between meals
- avoid fructose, galactose, and sucrose
This GSD involves the accumulation of limit dextrin-like structures in the cytosol.
Cori disease (type III)
This LSD is a mucopolysaccharidosis that involves developmental delay, gargoylism, airway obstruction, corneal clouding, and hepatosplenomegaly.
Hurler syndrome
Enzyme deficiency in Krabbe disease
Galactocerebrosidase
This physiologic process is responsible for the "second-wind" phenomenon observed in McArdle disease
Anaerobic metabolism is blocked; Increased muscular blood flow leads to switch to aerobic metabolism and a "second-wind"