for the lethal GBED allele, meaning both parents must be heterozygous for the allele. A blood test 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. Carrier frequency has been estimated at 7.1% in the Quarter Horse, 8.3% in the Paint Horse, and as high as 26% in Western Pleasure horses. This genetic disease has been linked to the foundation Quarter Horse sire King P-234. References "Testing for Genetic Diseases" Equus 353, pp 40–41. External links University of Minnesota: Neuromuscular Diagonistic Laboratory: Glycogen Branching Enzyme Deficiency (GBED) UC Davis: Veterinary Genetics Laboratory: Glycogen Branching Enzyme Deficiency (GBED) VetGen: Veterinary Genetics Services: Glycogen Branching Enzyme Deficiency (GBED) Horse diseases American Quarter Horses