Meta-Biol

• Pathways

Glycogen synthase 1 (GYS1) normally catalyzes the addition of glucose residues to a growing glycogen molecule. In its absence, glycogen synthesis fails. GYS1 ("muscle") is widely expressed in the body and its deficiency is most prominently associated with exercise intolerance and cardiomyopathy (Kolberg et al. 2007; Cameron et al. 2009). Two human GYS1 mutations have been described. The one annotated here is a nonsense mutation (Kolberg et al. 2007); no glycogen is detectable in microscopic studies of skeletal and cardiac muscle from affected individuals. The other is a frame-shift mutation predicted to encode a truncated protein with an abnormal carboxy terminus (Cameron et al. 2009).