Question on LP, liver shunt genetics
 

I'm curious: are the genes for these conditions (or other conditions endemic to yorkies) known? Are they caused by a single gene, or linked? Are they caused by recessive genes?

Also, since these conditions turn up later in life, how do you know your breeding stock will not pass this condition on to puppies? Does anyone here have lines they are 100% (or 99% ;) ) positive will not have any of these problems?

Just looking to learn more. Thanks!

Dr. Sharon Center is currently working on trying to find a genetic marker for liver shunts. Here is some information about her grant:

2009 Grants Funded

Thanks, LM! Am I correct in reading that the grant is for $3K? I saw several studies listed on there, and I couldn't tell how much money was given in total.

Testing conducted by Dr. Center & Dr. Tobias have not been identified as conclusive.

Bile Acid testing your dogs only proves they do not have the disease, but it doesn't prove they aren't carriers. As stated above research on discovering the DNA Marker is still ongoing. We're told that it is close, but how close????

It definately is a recessive gene...and not rear it's ugly head for 9 generations. It's just a matter putting the right 2 dogs together.

Dr Tobia's conducted studies; breeding two shunt dogs and they never produced a shunt puppy. She's bred two dogs whose bile acids were with in normal limits and they produced shunt puppies. She's researched yorkies and found that shunt puppies had 1 common ancestor...and then non-shunt puppies had the same ancestor in their pedigree too. So, to date all research is non-conclusive, but it is being continued.

Interesting. I thought liver shunt was something that could be triggered late in life, but you are saying that puppies can immediately exhibit it?

Do these results suggest anything, like linked genes, or that environment is likely a big factor?

What other breeds suffer from liver shunt?

Also, for the breeders: since many of you stay in touch long term with your buyers, do you get notified and keep records if a dog develops this condition (or something else)?

Thank you..that is what I thought but I was not comfortable posting about this..I was under the impression LS more in the first year of life and MVD after? I know that is a general statement and could be off but maybe that is what QuickSilver is thinking.

There are two types of shunt, rears it's ugly head, early on in life. The other is aquired shunt.

I know of MVD dogs that it was identified as pups. And then I know of dogs that never showed any outward signs of shunt and discovered through a blood test, revealing abnormal bile levels at the age of 3.

There is some information available on the Canine Inherited Disease Database.
Canine Inherited Disorders Database - Introduction
A lot of the inherited disorders are either unknown inheritance, recessive, or recessive with incomplete penetrance (which means that some dogs who have the genes get the disease, some do not, not really helpful). Careful record-keeping is probably the key to lowering or elimination of most disorders. Although records may be available for breeding dogs, it is hard to collect data about siblings that were never used in a breeding program. Using the healthiest dogs that have been tested for health issues is the best that can be done now, until there are genetic markers for all the inherited disorders, it is still just a crap-shoot.

If one acess the YTCA.org site and goes to the Health Foundation Page. There is information on Dr Center's newest Bile Acid Protocol as well as questions and answers from the seminar she held in in TN.

All dogs' livers are shunted extrahepatically before birth. It is a problem when the shunt doesn't close as it should shortly after birth.

The research that's been done is inconclusive and confusing....shunt dogs having shunt-free pups and vice-versa.

My own personal opinion is that the cumulative effects of yearly vaccinations and monthly flea and heartworm treatments contribute to a toxic state that is more pronounced in small dogs. Research shows a clear link with small dogs having more reactions to vaccines than larger breeds. Also remember, heartworm and flea preventatives are NOT medicines, but pesticides.

We have seen birth defects before in children of parents (both human and animal) that bears out the disastrous effects toxins can have. Think of DDT in birds and the effects of Agent Orange on children of Vietnam vets and on the Vietnamese themselves. In the case of dogs, my thinking is that a female dog has all her eggs at birth and those eggs can be affected by the cumulative effects of toxins before they are fertilized.

The most direct genetic link I've seen with LS in dogs is with the Irish Wolfhound. By identifying and removing affected dogs from breeding, the incidence was reduced by about 50% in a relatively short time. I believe these were cases of intrahepatic shunts rather than extrahepatic shunts though and Yorkies are prone to extrahepatic shunts.

We all are looking for research to give us better guideposts but I have to wonder if environmental factors are being looked at enough.

LS is characterized as a congenital (present at birth) defect. There is no more certainty than this so far.

Thanks! Very interesting. I see Dr. Center has revised her protocol again. She is now recommending a bile acids test at 16 weeks and again at 6 months.

I think that her protocol was revised over a year and half ago. She continues researching Bile Acid Methods that reduce the affects to a pup. The fasting was found to be to hard on pups, leading to hyperglycemic attacks.

There was an article I posted somewhere on YT, I'll have to hunt it down, but not tonight. On Esbilac Supplement and the possible link to it's contribution to shunt.

I knew she had done away with fasting several years ago, but last I heard she had revised her BAT age from 16 to 20 weeks. I see now it's back down to 16 weeks, but she recommends retesting at six months. That's what's new, right?

I am so glad she is working so hard on this serious health issue.

http://www.yorkietalk.com/forums/bre...ment-milk.html
Is this it?

Yep! Thanks.