Re: [PyrNet-L] Health discussion/Dwarfism

["Tracy Bassett" <espinay@dynamite.com.au>]

>>Although it may be true that no one has heard of dwarfs in other
countries, it had to come from somewhere, right? I wonder if culling
is still a general practice in other countries as it was in this one
years ago. Now, a question. I have heard that there are several
different types of dwarfism in dogs as there are in humans. Is this
the case or not? I know of a dwarf who lived about 7-8 years and was
healthy. I have also heard of dwarves that were very sickly and died
as pups.   Barb Bowes <<

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 (as in German Shepherd
Dogs).  I have heard that it is possible to treat pituitary dwarfism in dogs
with human growth hormones, but that this is pretty expensive.

What form is found in Pyreneans?  I have not seen or heard of it in
Australia either (but ditto on Jan's comments that this does not mean I am
100% sure that none has occurred).

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

As for where the gene comes from - My understanding of genetics is pretty
basic, but 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 (due to some unknown factor, environmental or otherwise) - 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??

Tracy Bassett
espinay@dynamite.com.au
Canberra, Australia