View Full Version : Any Questions?
4th June 2007, 06:06 PM
Please feel free to ask me any questions here, I will try to answer them as honestly as possible but can only speak from my own personnal experience!
4th June 2007, 09:25 PM
Cathryn thanks for the background so far -- really interesting on how you made decisions about which pups to keep and how you make breeding decisions.
Boy you DO have a cavalier focused family when you met your husband because of a cavalier and got a cavalier from him on your wedding! :lol: Can you find another guy like that and ship him to Ireland? :)
I thought I'd add a couple of links for people: the breeding grades and recommendations that Cathryn mentions are here:
Just a small clarification; an 'A' dog can have the malformation (almost all dogs seem to have it) but doesn't have syringomyelia and is over 2.5 years old. :)
Cathryn also mentions Martin Deutschland's presentation: I have notes for it here, where you need to scroll down to Paper 8:
You will also find a link directly to the slides and to his own abstract for the talk.
That will enable people to follow some of the fine detail of the things you are talking about.
One of the complications with this condition is that there doesn't seem to be a straightforward mode of inheritence for the condition. It seems to be carried on several genes (polygenetic) which need to combine in a certain way. That is why there isn't a straighforward Mendelian mode of inheritence (eg if there is one SM gene, and you know one parent has the gene and one doesn't have it, then there's a fairly straightforward statistical likelihood of a certain number of pups being affected, a certain number carriers but unaffected, and a certain number clear). Instead it seems that there are probabilities associated with different lines being more or less likely to produce symptomatic SM and the mode of inheritence is complex. But some early trials are showing that selecting clear dogs (A) for crossings is producing a lot of all A litters when pups are MRI'd as they mature. This indicates that choosing clearer dogs, even though they have the malformation that can cause SM, reduces the likelihood of SM developing at all. A lot of people misundersand this situation and keep talking about SM as being a fairly straightforward condition with a simple mode of inheritence. Early genetic work indicates this is very unlikely, unfortunately (it would be a lot easier to deal with if it were). Some early statistical work run on MRIs so far by a statistician/computer scientist indicates there are some lines that are looking much better than others for inheritence. The more breeders who MRI, the better the chance at finding other less affected and perhaps even unaffected lines. :)
A genetic test would hopefully help breeders to understand not just if a dog might produce SM but which of a selection of likely SM genes the dog has and therefore the best DNA profile to mate that dog to. Complicated!
Finally, a question! :lol: What is your scanning date? It is wonderful that so many breeders are now involved!
4th June 2007, 10:17 PM
Thanks for that Karlin, I tend to go off on a tangent and "assume" that people understand the gradings etc! icon_blshing
The scans are on Tuesday 12th June at 4pm, so I am going to be a gibbering wreck by then, it is , according to my satnav, a one and three quarter hour journey to Chester from where I am, so shall set off about 12:00-12:30pm, goodness knows what time I will be getting home, but it will be well worth it!
I seem to recall reading on one of the sites that they believe there are some 6 chromosomes that can affect the inheritance of SM, unlike my sister who has a PHD :yikes: I am not scientifically minded, I do believe however that if you REALLY want to know about something then you will absorb it, I am still at a "toddler" stage on this so bear with me if I blunder now and again icon_blshing :sl*p:
4th June 2007, 10:30 PM
We like the tangents! :) I am just trying to fill in some background from time to time and offer links to let people pursue more background if they'd like. I have huge amounts of material on the SM site, much of it directly supplied by researchers themselves and the site is regularly reviewed for accuracy by Clare Rusbridge and Penny Knowler. So people can be assured they are getting accurate information from these particular researchers, inasmuch as is known at his time. :thmbsup:
Yes there are 6 areas identified as of interest in the prelim DNA work. The current status of this work is outlined by Clare Rusbridge in the paper she gave at last November's Sm conference in London and which I have summarised from the talk in Paper 2 here:
I summarised the key points at the start (which I meant to do for all the papers, but never got around to I'm afraid!):
Identifying genes responsible for the Chiari-like malformation (CM) with or without syringomyelia (SM) will help a better understanding of the underlying pathogenic mechanisms for better diagnosis, prognosis and clinical management of the condition
DNA research should also help unravel the embryonic development of the affected structures that create the malformation
We have constructed a 10,000 dog genealogy of related CKCS spanning 24 generations across three continents (N America, Australia and Europe) and established a DNA collection of 100 samples mainly from CKCS but including 6 other affected breeds (King Charles Spaniels, Yorkshire terrier, Bull terrier, Boston Terrier, Brussels Griffon, Chihuahua)
10 dogs were selected for genotyping with 122 markers distributed among the 38 autosomes and X chromosomes. Next, we recently completed the genotyping of 173 CKCS over 249 microsatellite markers distributed over the 28 autosomes and the X chromosome
Because CKCS dogs are so closely related and from a closed gene pool, linkage disequilibrium (LD) analysis is a promising strategy for gene mapping.
Preliminary results of LD analysis identified six statistically significant regions on six associated chromosomes. Possible candidate genes are in the Hox and Pax gene families
Which may be far more detailed and technical than people care for! :lol: But there is much for any general readership in the papers summarised there and people can go to the slides through links to the club site, and also read each speaker's abstract. There's also of course the details of the talk summarised above.
4th June 2007, 11:04 PM
According to the breeders recommendation(per Karlins post)-- a grade of an A can have a small pocket of fluid (syrinx) of less than 2mm betweem the C2-C4 . Right?
4th June 2007, 11:15 PM
Yes that is correct, a grade A is given to dogs over the age of 2.5 yrs of age. Syringomyelia absent or less than 2mm central canal dilation in the C2-C4 region only.
5th June 2007, 02:57 PM
Just wanted to wish you all the best for scan day, I had Taffy done at ChesterGates and was a wreck all day, had just over a 3 hour drive and how I made it there in one piece is beyond me, but it was worth it in the end
5th June 2007, 04:15 PM
That's right, sorry about that; it can be a very small dilation at age 2.5 or over for the A grade (it was the old A* grade that was no syrinx at all, but that grade has since been dropped). BTW Geoff Skerritt doesn't give grades and the grading certificate as far as I know -- he also does not indicate the existence or not of the malformation on his certificate (I have two of those). I think the info would need to be verified (eg the csans re-read) for grading by a neurologist who is offering grades, if people want a formal grade. I am sure the club is aware of this, though.
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