Normal glycogen synthesis and degradation are required for maintenance of blood glucose concentrations during periods of fasting. The hepatic glycogen storage diseases comprise several inherited diseases caused by abnormalities of the enzymes that regulate these pathways. Although hypoglycemia is the cardinal manifestation of all the hepatic glycogenoses, there is a wide spectrum of severity. In many patients the hypoglycemia is unrecognized leading to delayed diagnosis. Traditional fasting studies may not appropriately identify all the disorders of glycogen synthesis and degradation, and specific testing is often required. All the glycogen storage diseases are treated with continuous glucose delivery, either by intermittent administration of uncooked cornstarch or frequent feeds during the day and overnight intragastric feeding, in an attempt to maintain blood glucose concentrations above the threshold level for glucose counterregulation. During periods of stress, exposure to pharmacological doses of glucocorticoids, or both, severe lactic acidosis can occur in type I GSD despite maintenance of normal blood glucose concentrations. Patients with the glycogen storage disease are at risk for long-term complications that are type-specific, including hepatic adenomas, hepatocellular carcinoma, focal segmental glomerulosclerosis, anemia, and cardiac dysfunction. Minimizing the metabolic abnormalities of these disorders may decrease the risk for long-term complications. The achievement of optimal biochemical control continues to be a challenge and requires individualized treatment regimens. With modern management, good biochemical control can be achieved, and the prognosis for all the glycogen storage diseases has improved considerably.
*Assistant in Endocrinology, Children’s Hospital Boston, Instructor in Pediatrics, Harvard Medical School, Boston, Massachusetts.
†Director, Diabetes Program, and Chief, Charles A. Janeway Medical Firm, Children’s Hospital Boston, Associate Professor of Pediatrics, Harvard Medical School, Boston, Massachusetts.
CHIEF EDITOR’S NOTE: This article is the 36th of 36 that will be published in 2002 for which a total of up to 36 Category 1 CME credits can be earned. Instructions for how credits can be earned appear after the Table of Contents.
Address correspondence to: David A. Weinstein, M.D., M.M.Sc., Division of Endocrinology, Children’s Hospital, 300 Longwood Avenue, Boston, MA 02115. Telephone: 617-355-2451; Fax: 617-734-1369; E-Mail: David.Weinstein@tch.harvard.edu
The authors have disclosed that they have no significant relationships with or financial interests in any commercial company pertaining to this educational activity.