Junctional epidermolysis bullosa (JEB), or Epitheliogenesis Imperfecta (EI), is a genetic disorder found in horses. Although affected foals may be born healthy, they die at birth.

Breeds affected

JEB has documented in Belgian drafts, American Cream Draft, Breton drafts, Comtois, and American Saddlebreds. Of these horses, 12% of Belgians and 4% of Saddlebreds are thought to carry the disorder.

Symptoms, Causes, and Prognosis

JEB causes defect in the action of the protein needed to connect the dermis to the epidermis. This produces many symptoms, including:

• hair and skin loss, especially over pressure points (hock, elbows and stifle, fetlocks, and hip). These patches of skin loss grow over time.
• sloughing of the hoof, and ulcers around the coronary band
• oral ulcers, especially around the teeth
• incisors in at birth

There is no known treatment. Foals are usually euthanized after diagnosis, due to the pain associated with the disease. Those that are not euthanized usually die of infection within 2 weeks.

Sources

"Testing for Genetic Diseases." Equus 353. pp 42-43.