Purpose or Case Report: Learning Objectives: This educational exhibit will review glycogen storage diseases and the imaging findings of these disease processes using a multimodality approach. We will also review complications and discuss the treatment and role of imaging as a measure of treatment response.
Methods & Materials: Background: Glycogen storage diseases (GSD) are a unique set of inherited disorders that affect glycogen metabolism. To date, more than 12 types of GSD are recognized and are sub-divided by enzyme deficiency and affected tissue. These autosomal recessive conditions affect 1 in 50-100,000 births. The University of Florida in Gainesville is home to the largest clinical research program for GSD in the world and provides care for pediatric patients with GSD from over 30 countries.
Results: Imaging Findings: Depending on the exact enzymatic deficiency these patients can present with unique manifestations of the disease process on various imaging modalities. Types I, III, and IX compromise 80% of the hepatic GSD. Hepatic adenoma formation is often seen in Type I GSD. This can be complicated by malignant transformation into the hepatocellular carcinoma. Renal enlargement and nephrocalcinosis can be seen as well. Apart from the propensity to develop recurrent or chronic bacterial infections patients with type Ib disease are clinically and metabolically indistinguishable from type Ia disease. Those with type Ib can often also manifest with delayed bone maturation and demonstrate a variety of findings on radiography. Patients with type IIIa disease can manifest cardiomyopathy often assessed on cardiac MRI (magnetic resonance imaging). Neuromuscular manifestations are a mainstay of more rare subtypes. Osseous manifestations are also appreciated in many types of glycogen storage disease subtypes.

We will use a series of cases to demonstrate the typical imaging findings associated with various types of glycogen storage diseases and their complications. We will also demonstrate how imaging can be used as a measurement of treatment response. We will provide examples using a multimodality approach with radiography, US (ultrasound), CT (computed tomography) and MRI (magnetic resonance imaging).
Conclusions: Glycogen storage diseases offer an interesting variety of multimodality imaging findings. Accurate recognition of these findings allows the pediatric radiologist to alert the referring physician to complications and help guide treatment for this unique group of patients.