Equine Genetic Diseases

Some of the most dangerous diseases affecting horses are hereditary, meaning they are influenced by genetics.

  1. Glycogen Branching Enzyme Deficiency

    • GBED is a genetic disease found in quarter horses and related breeds. The disease is always fatal, with death occurring in utero or within four months of birth.

    Hereditary Equine Regional Dermal Asthenia

    • This disease is most commonly found in quarter horses descending from the great stallion Poco Bueno. Horses with HERDA will typically only live two to four years. This disease causes layers of skin to separate because of a collagen defect.

    Hyperkalemic Periodic Paralysis

    • Horses with HYPP have lineage that includes the legendary quarter horse stallion Impressive. HYPP horses often experience muscle problems, seizures and even heart failure from the disease.

    Recurrent Exertional Rhabdomyolysi

    • This disease a genetic form of tying up that is common in young thoroughbred fillies, especially those in race training. RER can be managed by feeding a low-starch diet and carefully managing exercise.

    Polysaccharide Storage Myopathy

    • PSSM is a genetic form of tying up that includes muscle damage and inability to move. In contrast to RER, this disease affects quarter horses, draft breeds and crossbred horses. PSSM can also be managed through reducing starch and managing the horse's exercise regime.

    Overo Lethal White Syndrome

    • This disease affects paint and pinto horses. Lethal white foals are pure white and have an incomplete digestive tract. OLWS is always fatal in utero or within a few hours of birth. To prevent lethal white foals, breeders should not cross two horses with overo coloring or breeding.