RodRussell
Well-known member
Maybe Cavaliers Don't Even Have Chiari-like Malformation (CM)! Read about it here:
http://www.cavalierhealth.org/editorial.htm
http://www.cavalierhealth.org/editorial.htm
Rod,
Has there been any publications about the Brussel Griffins study at UGA. A friend went to to a seminar several months ago about the study.
Since, SM in griffins have been found without CM, it makes you wonder.
Maybe Cavaliers Don't Even Have Chiari-like Malformation (CM)! Read about it here:
http://www.cavalierhealth.org/editorial.htm
...So, are the Smaller Heads that many Cavaliers have to-day , could be involved in these findings. ...
No, Bet. And, I am unaware that cavaliers' heads are smaller today than thirty or forty years ago. Where is that research to be found?
MAYBE CAVALIERS DON'T EVEN HAVE CHIARI -LIKE MALFORMATION(CM)!
In Dr Rusbridge's Thesis ,she mentioned the Minaturization of Cavaliers , what was Minatureized in our Cavalier Breed.
Was it their Bodies , Heads or what ,perhaps some -one will tell me?
Bet
the brain is too big?? How the *cuss* does that happen. I also thought I had read that the cavalier skull finishes growing too soon...that the bones fuse too early. Really all of this is very confusing especially to a newbie that has future plans for breeding. What I wish would happen is more cavaliers get scanned and have dna samples for research.
I really don't think anyone can say the skulls are smaller today than years ago, because no one has done any measurements. I would like to see numbers before that statement can be made because I don't really see any head differences in older pictures I have seen. I have actually noticed a few dogs in the ring with quite large heads. I have also seen a few pin-heads but I don't think size of head would be a reason to say this dog will be more likely for SM or not. Not enough research has been done...not enough dogs have been scanned. JMO.
Rod withall due respect I think you have misread the research -- which all pretty much agrees that there is a mismatch between 1) the skull being too small due to a formation similar but not the same as the Chiari Malformation in humans and 2) the brain having a larger volume that would be the norm for a breed of the cavalier's size. So the bone stops growing at a point when the brain keeps growing. My understanding from human specialists is that this too is what seems to happen with Chiari. Have any of these researchers actually agreed that they would not call this problem CM? ...
... But no matter how confusing, I think both those approaches still demonstrate that *all* these researchers and the ones cited in other papers define the issue as one of a malformed bone at the base of the skull which does not grow in accordance with brain development and therefore, due to a mismatch between resulting skull volume (caused by CM) and brain size, ends up compressing the hindbrain in a way similar to Chiari malformation in humans. ...
...It might be more, common but to say it is only this breed is not correct. ...
Rod withall due respect I think you have misread the research -- which all pretty much agrees that there is a mismatch between 1) the skull being too small due to a formation similar but not the same as the Chiari Malformation in humans and 2) the brain having a larger volume that would be the norm for a breed of the cavalier's size. So the bone stops growing at a point when the brain keeps growing. My understanding from human specialists is that this too is what seems to happen with Chiari. Have any of these researchers actually agreed that they would not call this problem CM?
I think it would be unfortunate if breeders now misunderstand this all to mean there's no CM and that SM is the issue. There is clear evidence from the genome work that there are separate genes for CM and SM -- a key initial finding -- and that while not all CM dogs go on to get SM, all dogs with SM have CM. In about a fourth of cases dogs show symptoms from CM alone (this is much much higher in humans where Chiari is more common and causes the most pain). Some very eminent human SM specialists who attended both the SM events in the UK both agreed with a description of CM in dogs that is like, but not the same as, Chiari maformation.
Understanding the relationship between the genes for CM and those for SM and why some dogs switch on the SM genes and some do not is considered a quite critical part of current research.
From some breeder posts in reply to your posting elsewhere, I can see some already totally misunderstand what the genome research is about and ow will run with this interpretation as defense of ... well whatever misreadings they already have of existing research.:sl*p:
The issue of name for the condition was already debated at length and CM was chosen precisely because it was NOT meant to mislead people into confusing Chiari with a Chiari-like malformation. But a lot of neurologists continue to call CM 'Chiari malformation' in dogs (including some who were amongst the group at the meeting, that decided the condition should not be called Chiari malformation or COMS......go figure). But no matter how confusing, I think both those approaches still demonstrate that *all* these researchers and the ones cited in other papers define the issue as one of a malformed bone at the base of the skull which does not grow in accordance with brain development and therefore, due to a mismatch between resulting skull volume (caused by CM) and brain size, ends up compressing the hindbrain in a way similar to Chiari malformation in humans.
For what it is worth I know of geneticists and other specialists including some who have not said this publicly who believe the situation for the breed is quite dire and that it probably will not survive many more (human) generations before it faces too high a risk of seriously compromised and painful life if drastic action isn't taken. Given club breeder opposition to nearly every single thing done by researchers and the BVA to try to improve health, including the screening schemes they themselves demanded (but don;t want to follow once put in place) I cannot imagine the breed can continue much longer without outside international regulation on breeding.
Even people like Dr Jeff Samson, the Kennel Club's own genetics specialist, are now saying they think the breed is under threat and what he has stated at a couple of breed events is quite different from what he said in Pedigree Dogs Exposed. He now accepts probably 70% eventually have SM -- that is a shocking, shocking percentage with a serious neurological disorder considered one of the most painful and horrific health issues that humans can get. In a human population, that would bring national enquiries and massive funding to find out what is going wrong.