GBED: Glycogen Branching Enzyme Deficiency By: Kaylea Foust and Alison Billas

Classification of GBED Autosomal (non-sex) recessive Foal must receive abnormal alleles from dam and sire

History and Background First research at University of Minnesota Funded by American Quarter Horse Association GBED first identified in foal in 2001 Two years later the gene responsible for the production of glycogen branching enzyme was found Located on equine chromosome 26

Cause of GBED Abnormal glycogen production Foals are unable to fully utilize glucose, the body’s primary source of energy Glycogen structures are not properly branched GBE protein is absent Only Cross Resulting in GBED G g GG Gg gg

Animals Affected Affects about 10% of Quarter horses and related bloodlines All identified GBED horses have been Quarter or American Paint horses Breeders have 25% chance for a GBED foal

Signs/Symptoms of GBED Late term abortion and still births are common Average life span: Four months Always lethal

Signs and Symptoms of GBED If the foal is alive: Weakness and low birth body temperatures Low white blood cell count Sudden death due to heart failure or seizures High respiratory rate and weak muscles Contracted tendons in all legs Overall weakness and inability to stand up

Prevention and Treatment Bottle feeding the foal and assistance to stand up helps the foal to grow stronger Minnesota researchers discovered the genetic defect Developed a test using DNA samples to determine carriers Pull out 10 mane or tail hairs from dam or sire To determine foal status, liver or muscle necropsies are preferred

Bibliography http://www.cvm.umn.edu/umec/