Glycogen branching enzyme deficiency
Encyclopedia
Glycogen Branching Enzyme Deficiency (GBED) is a genetic disease affecting horse
s, especially American Quarter Horse
s and related breeds.
, the horse's brain, heart muscle, and skeletal muscles cannot function, leading to rapid death. This condition may be diagnosed with a muscle biopsy. Most foal
s with GBED are aborted or stillborn, and those that survive live only for a few months. Symptoms include general weakness, contracted tendons, seizures, cardiac arrest, and sudden death. There is no known treatment.
for this allele was developed by the University of Minnesota
College of Veterinary Medicine and is licensed to the UC Davis Veterinary Genetics Laboratory. Using this, breeders can avoid crosses that could produce GBED foals, and eventually selectively breed
it out. Initial samples suggest that about 10% of Quarter Horses are carriers.
This genetic disease has been linked to the foundation Quarter Horse sire King P-234
.
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s, especially American Quarter Horse
American Quarter Horse
The American Quarter Horse is an American breed of horse that excels at sprinting short distances. Its name came from its ability to outdistance other breeds of horses in races of a quarter mile or less; some individuals have been clocked at speeds up to 55 mph...
s and related breeds.
Diagnosis, Symptoms, and Prognosis
Lacking an enzyme necessary for storing glycogenGlycogen
Glycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...
, the horse's brain, heart muscle, and skeletal muscles cannot function, leading to rapid death. This condition may be diagnosed with a muscle biopsy. Most foal
Foal
A foal is an equine, particularly a horse, that is one year old or younger. More specific terms are colt for a male foal and filly for a female foal, but these terms are used until the horse is age three or four. When the foal is nursing from its dam , it may also be called a suckling...
s with GBED are aborted or stillborn, and those that survive live only for a few months. Symptoms include general weakness, contracted tendons, seizures, cardiac arrest, and sudden death. There is no known treatment.
Causes
The disease occurs in foals who are homozygous for the lethal GBED allele, meaning both parents must be heterozygous for the allele. A blood testBlood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....
for this allele was developed by the University of Minnesota
University of Minnesota
The University of Minnesota, Twin Cities is a public research university located in Minneapolis and St. Paul, Minnesota, United States. It is the oldest and largest part of the University of Minnesota system and has the fourth-largest main campus student body in the United States, with 52,557...
College of Veterinary Medicine and is licensed to the UC Davis Veterinary Genetics Laboratory. Using this, breeders can avoid crosses that could produce GBED foals, and eventually selectively breed
Selective breeding
Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...
it out. Initial samples suggest that about 10% of Quarter Horses are carriers.
This genetic disease has been linked to the foundation Quarter Horse sire King P-234
King (horse)
King, often known as King P-234 was an outstanding early Quarter Horse stallion who influenced the breed throughout the early years of the American Quarter Horse Association .-Life:...
.