When you can’t degrade glycogen

Your brain, blood and muscles depend almost entirely on dietary glucose as a fuel source so your body must store the sugar for continual supply [1p733]. If you go without eating for a while or jog a mile or two you’ll find yourself relying on glycogen for energy [1p733]. The long-branched glucose polymer acts as a store of glucose molecules, ready for the moment’s need [1p733]. But imagine having inherited a defective gene that resulted in not allowing your body to degrade glycogen stores.

If it wasn’t for Mendelian genetics, von Gierke’s disease may never have been completely understood [2]. Also called type 1 glycogen storage disease, the inherited disorder was found in 1952 using Mendel’s principles to result from a defective gene that causes the lack of glucose-6-phosphate [2 & 1p740]. The enzyme is necessary for catalyzing the final step in gluconeogenesis and glycogenolysis, which is needed for synthesis of glucose from noncarbohydrates precursors and removal of glucose from glycogen when blood glucose levels are low [1p740].

Without an ability to degrade glycogen, those with the disease suffer from low blood sugar between meals that can reach dangerous levels, and excessive accumulation of glycogen in the liver, muscle and in the tubules of the kidneys that can create further health complications [1p740 & 3]. Symptoms include an enlarged liver; puffy cheeks and limbs; a swollen belly; constant hunger; stunted growth; delayed or underdeveloped puberty, gout, easy bruising and nosebleeds, fatigue, and irritability [3].

Living with von Gierke’s disease requires avoiding low blood sugar through frequent meals that include carbohydrates and feeding tubes used at night [3]. Because lactose and fructose can’t be broken down properly, milk and fruits are usually avoided [3].


1. Denniston KJ, Topping JJ, Caret RL. General, Organic, And Biochemistry, 5th ed. New York: McGraw Hill; 2007.
2. Lorentz CP, Wieben ED, Tefferi A, Whiteman D, Dewald G. Primer on medical genomics part I: History of genetics and sequencing of the human genome. Mayo Clin Proc. 2002;77:773-782. Available at: http://www.mayoclinicproceedings.com/inside.asp?AID=165&UID=. Accessed on November 19, 2008.
2. MedlinePlus. Von Gierke disease. Medical Encyclopedia. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000338.htm. November 19, 2008.

Published by David Despain, MS, CFS

David is a science and health writer living on Long Island, New York. He's written for a variety of publications including Scientific American, Outside Online, the American Society for Nutrition's (ASN) Nutrition Notes Daily, and Institute of Food Technologists' (IFT) Food Technology magazine and Live! blog. He's also covered new findings reported at scientific meetings including Experimental Biology, AAAS, AOCS, CASW, Sigma Xi, IFT, and others on his personal blog "Evolving Health." David is also an active member of organizations including the National Association of Science Writers (NASW), the American Association for the Advancement of Science (AAAS), the American Society for Nutrition, the Institute of Food Technologists, and the National Audubon Society. David has a master's degree in human nutrition from the University of Bridgeport, and a bachelor's degree in English from University of Illinois at Springfield. He also earned his Certified Food Scientist credential from the Institute of Food Technologists.

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