Glycogen storage disease Type VIII is a rare genetic metabolic disorder characterized by an accumulation of glycogen in the central nervous system and can result in substantial abnormalities and dysfunction of the central nervous system. Glycogen storage disease Type VIII affects the X chromosome and results in a deficiency of a liver enzyme called phosphorylase kinase. This deficiency eventually leads to excessive deposits of glycogen in the liver (National Organization for Rare Disorders [NORD], 2001). Because it is an X-linked, recessive genetic disorder, it is more likely to be masked in females and expressed in males (NORD, 2001).