Overo Lethal White Foal Syndrome: Equine Aganglionic Megacolon
  by Robert N. Oglesby DVM

Lethal white is a genetic defect in foals of matings of some overo mares to some overo stallions. The nervous system to the bowel of the fetus does not develop normally resulting in impaction colic and death shortly after birth. Experience suggests that the incidence of this defective gene is quite high. Currently it appears to be a simple recessive mode of inheritance. What that means is that if a horse carries one of the genes he shows no signs of illness, but if he inherits a pair of the defective genes, one from the mare and one from the stallion, he will contract the problem. It is important to realize that even if the breeding animal only carries one of the genes he can perpetuate the problem in the breed. Passing on this gene to other healthy appearing horses. Recently the University of Minnesota Veterinary Genetics Lab has developed a test to detect the unapparent carriers. This is the first step toward eliminating this heart breaking disease in the breed.

You have just read the introduction to one of our nearly 800 articles on horse care, diseases, and training. It includes a description of the contents of the unabridged version. As a guest you can access this article two different ways: either purchase the article or become a member and take advantage of all the benefits Horseadvice.com has to offer. Check out our Membership Drive Discount below but hurry. This is for a limited time!