Define GBED.

• A. Glycogen Branching Enzyme Disease: terminates protein synthesis which can result in late-term abortions or death in foals shortly after they are born
• B. Glycogen Breakdown Enzyme Disorder
• C. Glycogen Basic Endurance Disorder
• D. General Behavior and Epilepsy Disorder

Answer: (A)

GBED, or Glycogen Branching Enzyme Disease, is a fatal inherited metabolic disorder in foals caused by a mutation in the gene for glycogen branching enzyme. This enzyme normally adds branches to glycogen; when it’s defective, glycogen cannot be formed properly, so energy storage and glucose regulation fail. Affected foals are typically lost late term in pregnancy or die shortly after birth. That’s why the correct choice identifies the disease by its name and notes the perinatal fatal outcome. The described mechanism should focus on glycogen synthesis, not protein synthesis, and the other options refer to unrelated or nonsensical conditions.