Arabians, pure and part-bred
Friesians, pure and part-bred
Warmbloods, pure and part-bred
Fell Ponies, Dale Ponies and Gypsy horses, pure and part-bred
Quarter horses and related breeds, pure and part-bred
Saddlebred and related breeds, pure and part-bred
Akhal Teke, pure and part-bred
Connemara, pure and part-bred
Coat colour tests
Glycogen branching enzyme deficiency (GBED) is a genetic disorder found in pure and part-bred Quarter Horses and Paint horses. GBED usually causes abortions. Foals that survive until birth show severe weakness, seizures, and low body temperature. GBED is always fatal.
GBED can happen in both male and female foals. Foals with GBED need to have gotten the GBED mutation from both parents, not just one. When a horse is passed the GBED mutation from just one parent it is called a GBED carrier. You cannot tell from performance or appearance that a horse is a GBED carrier - you need to test to find out.
Don't breed two GBED carriers to one another. If you do, you may lose the foal to GBED.
The GBED test is part of the 5-panel and 6-panel. Our test is based on the DNA sequences and information in Ward et al, 2004.
GBED can be found in:
All known cases have occurred in descendents of Zantanon, a QH stallion born in 1917.