After much research into the reason we ended up with this cute white foal, Misty, we are HAPPY to report that Misty is NOT a carrier of the Lethal White gene found in Overo, Tobiano and other horses with pinto or paint bloodlines. The Sabino pinto color pattern doesn't usually manifest this genetic defect. Below are links to web sites discussing the letal white syndrome. Some are quite easy to read and others are more detailed in genetic information.

Letal White is a genetic defect found mainly in overo pinto color patterned foals. It appears in Paint horses mostly, but can appear in any breed. The defect must be carried by both parents, and when it is the foal generally dies within 3 days of birth. The defect affects the intestinal track making it impossible for the foal to survive.

Horses can be carriers of this defective gene. A blood sample sent in for genetic testing can determine this. If you are planning to breed your pinto horse (Paint especially), to an overo, be sure both parents are tested... mare and stallion. Responsible Paint breeders will usually have had their overos tested. Tobianos can carry the defective gene, too, so they should also be tested. If you choose not to have the horses tested, you are taking a chance, but the odds are about 50%.

Color Patterns In Pinto Horses - A HPF Article

LINKS -
    * Mammalian Genome
    * Homozygous Tobiano Dies of Lethal White

Breeds of Horses

- Lethal White Syndrome