Re: [pyrnet] Dwarfism

[Kshoffman@aol.com]

In a message dated 09/29/2000 7:43:14 AM Eastern Daylight Time, 
pyreau@erols.com writes:

> I agree, Kelly, that epilepsy, heart disease and luxating patella are
> very worrisome and in some ways perhaps more serious.  Still, I
> would hate to think of  people deliberately breeding for dwarf Pyrs.

As would I, Charlotte, but unfortunately in many ways when breeding dogs we 
have to pick and choose our battles, or much better said, prioritize what we 
might be willing to give and take on at various stages of the game both on an 
individual breeder level and on a breed wide population level.  I suppose I'm 
saying that I personally am more concerned with a few other things I consider 
to be a greater threat to the breed in the long run than dwarfism.  Now 
that's not AT ALL to say it's a mutually exclusive proposition to attempt to 
control dwarfism while attempting to control other genetic diseases, at least 
it shouldn't be.  But in the big picture, we can't get so focused (as a 
breed) on dwarfism that we let these other things sit on the back burner for 
any length of time.  Else we may be sorry down the road. ;-(

Just wanted to give a "heads up" not to forget other things have to be dealt 
with, and that realistically, we can't (necessarily) as a breed focus on one 
defect at a time before moving on to waging battle against another.  Have to 
consider the whole works in additions to the various parts and pieces. ;-)

> Also if this is a recessive gene and every time a carrier is bred 50%
> of the offspring are carriers, we could end up with a lot of carriers in
> a short period of time.  We could get to the point where it would be
> difficult to find a dog that was not a carrier.

I certainly suspect today we have more carriers in the gene pool than we had 
2-3+ decades ago, but I also feel that dwarfism to an extent is 
self-limiting, whereas the other defects mentioned are not necessarily.  It 
is my understanding that the dwarfism researchers feel a good percentage (a 
majority?) of Great Pyrenees dwarfs are sterile. (Linda will correct me if I 
am in error.)  Additionally, dwarfism can be detected early, and a good 
percentage of breeders are perfectly aware they have produced dwarfs (it's 
not an unknown fact to them, whereas the fact they've produced other later 
onset defects may well be) and hence can take some action to control it early 
on.  I would think (but don't know) most breeders are going to find dwarfism 
to be an undesirable outcome and thus very few IMO would/will purposefully 
attempt to perpetuate it. IOW, I suspect the vast majority of dwarfs will 
never go on to reproduce. I just don't necessarily see the same scenario 
unfolding over time with regard to some of the other health issues we might 
be facing as a breed.

To my way of thinking, that fact that most dwarfs won't go on to reproduce 
will to an extent keep the carrier rate in check, or at least keep it from 
cumulatively rising rapidly.  Additionally, many (probably most) breeders 
will choose of their own volition to eliminate known dwarf carriers from 
their breeding programs. Some will choose to completely avoid potential 
carriers as well, or at least they will think they are as some may not know 
enough facts, nor have the genetic education to actually do so.  Others may 
do neither -- avoid all potential carriers, eliminate all known carriers -- 
but I think right now there is a decent acceptable balance between those 
breeders who do/will use known and/or potential dwarf carriers and those who 
don't/won't.  I think (or maybe I just naively hope) the bulk of those 
comparatively few who may choose to work around a known carrier issue, rather 
than totally eliminate such individuals, are being cautious and are closely 
following their outcomes.  I think they are making efforts to contain 
potential negative outcomes, exercising some measure of control so as not to 
spread potential carriers throughout the entire gene pool and have a great 
impact further down the line.  Maybe I'm dead wrong.  I hope not.

Of course, if the necessary information was more publicly accessible, it 
could really make a big difference in how we keep the carrier rate in check, 
and even reduce the rate.  That type of "checks and balances" system, whether 
we like it being kind of an informal "big brother" approach or not, tends to 
work to some extent on a breed wide level, *if* the message and education is 
reaching enough breeders .

I believe (but don't have solid, tested data to back it up) that in Belgian 
Shepherds we have seen a decrease in the rate of epilepsy in the last few 
years to couple of decades or so.  I think a big part of this has been 
bringing the issue out into the open, talking about it more matter-of-factly, 
sharing data more freely, realistically accepting that perhaps some 
"carriers" will have to be cautiously and responsibly bred when taking many 
other things into consideration.  Certainly getting intensely into the 
research aspect, development of a genetic test, has also been a positive 
move.  All of these things which have dramatically increased awareness of the 
extent of the problem and brought it out into the open have created an 
environment more conducive to sharing data, but also created a type of peer 
pressure and "political correctness" that has resulted in a vast less number 
of breeders using affected individuals in their programs (IMO).  It's just 
not so easy to hide such anymore, to do so and keep it totally and 
effectively private.  I think these changes have likely caused a decrease in 
the rate of epilepsy affected Belgians from around 21-22% (as was one early 
estimate back in the early 80's) to around 15-17% (which is the current 
estimated rate).  That may not seem like a huge decrease to some, but in the 
big scheme of things and considering how slowly progress in areas such as 
this tends to come, I think it is a very positive thing.  I only wish we had 
some valid tested data that could confirm this and provide positive feedback 
to Belgian Shepherd breeders -- something uplifting and encouraging that 
demonstrates perhaps we are on the right track now in controlling and 
hopefully in the near future reducing this problem.  Any data available prior 
to the early 80's is for the most part anecdotal and the earliest published 
work was based on a much smaller sample than today's work, so we really have 
no way at this point to definitively demonstrate improvement has indeed 
occurred from say 1980 to present.

> This is a good reason to make every effort to determine
> some sort of marker.

Certainly a genetic test for dwarfism in Pyrs would be wonderful, but a 
linkage test (nor a direct gene test, for that matter, although I'll take the 
latter to the former) should not be construed as any type of salvation, 
merely as a tool; one additional piece of information that should be used for 
decision-making purposes.  Clearly, the more information we have from all 
angles the better -- with regard to dwarfism and with regard to everything 
else the majority would consider to be the most concerning issues facing 
Great Pyrenees as a breed today.

In my opinion, GPCA has one of the best, most progressive, most proactive 
health committees out there in comparison to other breeds and parent clubs.  
I just wanted to reinforce the message that we *collectively* as a breed must 
consider other things, must understand there is a juggling act of sorts that 
needs to go on here with regard to what shape the breed is in genetic health 
wise, and what can and should be done to exercise some measure of control 
over that now and well into the future.

*If* it should get to (or be at) the point where resources 
(time/effort/funding) for genetic research in the breed are limited, I would 
certainly not want to see all such resources being dedicated strictly to 
dwarfism.  I don't see that happening with the current health committee, 
thankfully.  Again, not saying dismiss or ignore the dwarfism issue, but am 
advising don't let other genetic health concerns/issues disappear off your 
radar screens, and do try to keep a balanced perspective.  And this is not 
directed at you, Charlotte, I'm sure I don't have to point these things out 
to you and many others.  This is simply food for thought for those out there 
who may not have considered some of these things.

I think now would be a good time to offer a public "thank you" to the GPCA 
Health Committee. ;-)  For those out there who aren't involved in other 
breeds, or who aren't GPCA or affiliated club members, and/or who don't 
really know how far behind some of these other breed clubs are in genetic 
health research/education areas in comparison to Pyrs, then perhaps you can't 
truly appreciate the efforts and accomplishments thus far of the GPCA Health 
Committee under the leadership of Linda Weisser and JoAnn Teems.  We're 
darned lucky and blessed to have them.

Kelley Hoffman
kshoffman@aol.com