Lethal White is a recessive disorder (meaning a copy from each parent is needed to affect the foal).  There are no homozygous OLWS horses. As the name depicts - Lethal White - means if the horse inherits to copies of the gene they will die.  OLWS foals are white in color and have blue eyes.  They are born looking normal and healthy but will not survive past a couple of weeks.  There is a genetic test available for OLWS.

Common Questions:

Do all Overo Horses carry the Lethal White gene?  NO

Will breeding 2 Overos together will 25% of the foals be Lethal Whites? Not necessarily - This percentage only applies if each parent is an OLWS carrier - since not all overos carry the OLWS gene this is not always the case.

Is it only overos that can carry OLWS?  No ... Tobianos, Solids and all Paint crosses are potential carriers.

Is it true that if a Paint is totally white it will not be an OLWS carrier? No... All White Paints are often carriers.

Are all totally white foals Lethal Whites? No

Can you tell if a horse carries OLWS by it's coat pattern? No

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Our main goal is to find the source horses for genetic diseases. In the meantime we also provide information to help Breeders, Buyers and Owners make good choices when breeding buying or selling their horses.

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