CM/SM in Cavalier relative ancestor breeds.

How is the situation with other Cavalier related breeds with regards to CM/SM.

Do these other similar Cavalier breeds have a better percentage.
- King Charles Spaniel (this breed actually is what our Cavs came from)
- Papillion (the other cousin breed)
- Japanese Chin (a very similar breed to the Cavalier at least in shape of head and muzzle)

By better I mean less incidence to the high percentage Cavs seem to have of the Inherited disease.

King Charles spaniels (English Toy spaniels) seem on anecdotal evidence to have a lot of SM as well -- I have spoken to a few owners and neurologists in the past. But breeders have been very reluctant to scan so there's no sense of a percentage. The other two breeds -- not enough scanned to really know. There is recent research that indicates those domed heads are not good news generally in any breed, though.

Here's what Dr Clare Rusbridge says on her website but this list is fairly old. I've also heard of quite a few crosses of these breeds with CM/SM:

What breeds are affected with CM/SM?
The Cavalier is overwhelmingly overrepresented for cases of CM/SM. There is no colour or sex predisposition. As shortened skull is a risk factor, any breed with a degree of brachycephalism and/or miniaturization could potentially be predisposed to CM/SM. To date the condition has been also reported in King Charles spaniels, Griffon Bruxellois, Chihuahuas, Yorkshire terriers, Maltese terriers, Miniature dachshunds, Miniature/toy poodles, Bichon Frisé, Pugs, Shih Tzus, Pomeranians, Staffordshire bull terriers, Boston terriers, French bulldogs a Pekingese, a miniature Pinscher and a couple of cats.

Click to expand...

From http://www.veterinary-neurologist.co.uk/part2.htm

Maybe someone else has more info on these breeds?

Griffons seem to be the second breed with most incidence of CM/SM - or at least they are the ones who get scanned and diagnosed more often. Interestingly, the modern Griffon was developed with, amongst other ancestors, the addition of a King Charles Spaniel in the 19th century - apparently you still get an occasional throwback with a silky coat, quite different from the normal rough hair. Hydrocephalus is admitted to be quite common in the modern King Charles, but breeders seem to be reluctant to connect this with CM/SM. But then, after 20 plus years of diagnosing CM/SM in Cavaliers, there are still Cavalier breeders in denial about it, saying it isn't a serious problem in the breed. I think the genes for CM/SM have been around a very long time, and Cavaliers were unfortunate enough to double (treble, quadruple) up on them in the 1920s when breeders used a very small gene pool to develop longer-nosed spaniels.

Kate, Oliver and Aled

It might in the end have been that today Cavs have some of the inherited problems cause of the way the original KCS was changed to become the different KCS we have today.

Lets hope to find light in the end of the tunnel.