# I was reading a thread below



## barrelbeginner (Jan 31, 2012)

what does lethal white mean? Someone said that two horses were frame which means the foal could be lethal white? whats that mean?


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## Dreamcatcher Arabians (Nov 14, 2010)

Here's a description in a nutshell: 

Lethal White Overo (LWO) syndrome, also called overo lethal white syndrome (OLWS), occurs when a horse is homozygous (*OO*) for the frame overo gene. This genetic disorder causes the intestinal system not to develop properly (involving aganglionosis of the bowel). The foal will die within the first 72 hours after birth when its first meals cannot be digested properly. The lethal white foal will be born almost pure white.

And a link to the entire article on the Animal Genetics Inc's site:
LWO - Lethal White Overo Testing


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## barrelbeginner (Jan 31, 2012)

oh no! thats not cool! thats sad


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## ThirteenAcres (Apr 27, 2012)

Breeding two frames will always present in a 1/4 chance of the foal being LWO as well.


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## bird3220 (Mar 20, 2012)

If the foal has a spot on it anywhere then they say the foal should live and be fine. Alot of the frame babies when their born almost solid white have markings on their ears and tops of their heads called "medicine caps/hats" and they say that is what saves them from being lethal white. I bought a pregnant mare who had the possibility of throwing a lethal baby, but thankfully he was not!!!


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## NdAppy (Apr 8, 2009)

Not true bird. they can have some color and still be a lethal white, it just won't be much color. It's better safe than sorry..


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## bird3220 (Mar 20, 2012)

I know that's why I said "should live". I was just telling her about the "medicine caps".


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## NdAppy (Apr 8, 2009)

It isn't something that you should go off of though. Lethal foals can and do have spots of color. 

Anyone breeding any breed of horses that is known to carry OLWs should do the ethically right thing and test all breeding stock.


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## bird3220 (Mar 20, 2012)

I know my mare is a carrier and after all that I've been going through she will NEVER be bred again!!!


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## OwnedByAlli (Nov 8, 2011)

Just want to know if I've got the genetics right: 
If you bred a frame overo (nO, right?) with a horse without the O allele at all, say a sabino or splash, there would only be a 25% chance the off spring was a carrier?? Or can other paint colours carry the O allele without showing the frame overo pattern and therefore pass on the gene also?


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## NdAppy (Apr 8, 2009)

N/O to N/N is a 50% chance of N/O offspring. 

Frame overo hides under other patterns and even on solid horses, hence why testing is a MUST for any breed that is known to carry the frame overo gene.


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## eclipseranch (May 31, 2012)

Dreamcatcher Arabians said:


> Here's a description in a nutshell:
> 
> Lethal White Overo (LWO) syndrome, also called overo lethal white syndrome (OLWS), occurs when a horse is homozygous (*OO*) for the frame overo gene. This genetic disorder causes the intestinal system not to develop properly (involving aganglionosis of the bowel). The foal will die within the first 72 hours after birth when its first meals cannot be digested properly. The lethal white foal will be born almost pure white.
> 
> ...


and 1 more reason why people should leave breeding to people who know what they are doing!!


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