Lethal White Syndrome - Lethal White Mimics

Lethal White Mimics

Foals affected with lethal white syndrome are not the only white, blue-eyed horses. There are other genes that produce healthy pink-skinned, blue-eyed horses with a white or very light cream-colored coat. For a time, some of these completely white horses were called "Living Lethals", but this is a misnomer. Before reliable information and the DNA test were available to breeders, perfectly healthy, white-coated, blue-eyed foals were sometimes euthanized for fear they were lethal whites, an outcome which can be avoided today with testing and a better understanding of coat color genetics. The availability of testing also allows a breeder to determine if a white-coated, blue-eyed foal that becomes ill is an LWS foal that requires euthanasia or a non-LWS foal with a simple illness that may be successfully treated.

• Double-cream dilutes such as cremellos, perlinos, and smoky creams, have cream-colored coats, blue eyes and pink skin. The faint cream pigmentation of their coats can be distinguished from the unpigmented white markings and underlying unpigmented pink skin. A similar-looking "pseudo double dilute" can be produced with help from the Pearl gene or "Barlink factor" or the Champagne gene.
• The combination of tobiano with other white spotting patterns can produce nearly white horses, which may have blue eyes.
• Sabino horses that are homozygous for the Sabino-1 (Sb-1) gene are often called "Sabino-white", and are all- or nearly all-white. Not all Sabino horses carry Sb-1.
• Dominant white genetics are not thoroughly understood, but are characterized by all- or nearly all-white coats.