Glycogen branching enzyme deficiency (GBED) occurs in newborn foals. This fatal disease is seen in Quarter Horses and related breeds. The foals lack the enzyme necessary to store glycogen (sugars) in its branched form and therefore cannot store sugar molecules. This disease is fatal as the heart muscle, brain and skeletal muscles are unable to function.
Drs. Stephanie Valberg and James Mickelson from the University of Minnesota, St. Paul first identified this deficiency. The Veterinary Genetics Laboratory, University of California, Davis has obtained a license from the University of Minnesota and has developed a diagnostic test that is now available to horse owners and associations.
Additional GBED information at the University of Minnesota.