Re: [PyrNet-L] Health discussion/Dwarfism

[darrell goolsbee <dgg@star-telegram.com>]

Tracy:

<< I have heard of two different types - not sure if there are more or
if these
> are correct (can anyone confirm?).  They are Chondrodystrophy (or
> Chondrodysplasia) which is abnormal growth of the leg bones and vertebrae
> caused by a simple recesive gene (found in Beagles among others); and
> Pituitary Dwarfism (or Hyposomatotrophism) which is a deficiency in
> pituitary stimulation of growth hormone production.>>

There may well be some pituitary dwarfs in Pyrs, but the majority (and
the simple recessive type that we're working on) would appear to be of
the chondrodystrophy type.

<< I believe that work is being done in GSD's to identify original
carriers???
> Would (is) the same thing be considered for Pyrs???>>

A study is being undertaken to find the marker for the dwarfism
recessive. Hopefully it will succeed, but there's no guarantee. And
since carriers are totally normal, there's no way to identify one, other
than the dog having actually produced a dwarf or guesswork based on
pedigree.

<<I seem to remember from something I saw or read in the dim
> distant past that it is possible for a single gene in a single animal to
> mutate.>>

There's some body of thought that perhaps a mutation may have occurred
here in the U.S., since dwarfism has not been reported elsewhere. But
that's only a thought.


<< the gene
> has no effect in that animal, and may not have an effect for several
> generations, but down the line somewhere when carriers decending from that
> original animal (who may no longer appear on the pedigree as such) are
> mated, their progeny may exhibit the feature inherent in that gene. Can
> someone confirm or explain this any better than my poor attempt??>>

You're exactly right on this. Any dog with a known carrier in its
pedigree theoretically has a 50 pct. chance of being a carrier, no
matter how many generations back the carrier. If a dog has been bred
quite a bit, you may be able to surmise that it's not.

Darrell Goolsbee
Fort Worth, TX