but I still wonder if, has been recently mentioned by Dr. Imelda McGonnell,that in Cavaliers the Cells she is Researching seem to be having an Abnormal Cell Division,that in a normal situation ,if the Brain is growing too much ,the Bone should keep up with it, but in Cavaliers this relationship is lost.
Could this be due to some-thing that happened in the 1930's ,when the Cavalier Skull was being altered to get the Flat Skull required for the Cavalier Breed from the Dome Shaped Skull of the King Charles Spaniels. ?Maybe this will be being considered by Dr I Mc Gonnell .
I think that Dr McGonnell might agree that Geneticists need to find the genes if we are to have a DNA test for Cavaliers.
Interestingly I note that Dr McGonnell mentions Fibrillin-1 and gives reference mentioning significant evidence for linkage to regions on chromosomes 9 and 15, and the following from this address.
http://findaphd.com/search/showproject.asp?projectid=20481
The Royal Veterinary College, University of London
Project Supervisor(s) Dr H Volk, Dr I McGonnell
The development of canine Chiari-like malformation in the Cavalier King Charles Spaniel
Canine Chiari-like malformation and syringomyelia is thought to be present in most Cavalier King Charles Spaniels (CKCS) in the UK, although the true prevalence is unknown. This condition is similar to human Chiari malformation, a common disease, the causes of which are unknown. Canine Chiari-like malformation is associated with severe pain and progressive neurological deficits which can lead to euthanasia. Treatment can only ameliorate the clinical signs and a complete remission of signs is rarely achieved. The main reason for treatment failure is that both the aetiology and pathogenesis is unclear. We hypothesize that it arises due to changes in the coordination of growth and development of the occipital bone and brain in the embryo and foetus.
Our first aim is to investigate brain and skull development in CKCS foetuses, to measure hindbrain/occipital skull ratio at birth, using computed tomography and high field (9.4 Tesla) magnetic resonance imaging (MRI). Our second aim is to use both the dog and chick embryo model to investigate if a candidate gene, Fibrillin-1, plays a role in skull and brain development by forming microfibrils and modulating Tgfb signalling. We will then investigate if mutations in this gene can produce characteristics of Chiari-like malformation. This will determine whether this gene contributes to the aetiology of this disease.
1. Rusbridge C, Knowler SP. Inheritance of occipital bone hypoplasia (Chiari type I malformation) in Cavalier King Charles Spaniels. J Vet Intern Med. 2004 Sept-Oct; 18(5):673-8
2. Rusbridge C et al. J Vet Intern Med. 2006 Syringomyelia: current concepts in pathogenesis, diagnosis and treatment; 20 469-79
3. Boyles AL, Enterline DS, Hammock PH, Siegel DG, Slifer SH, Mehltretter L, Gilbert JR, Hu-Lince D, Stephan D, Batzdorf U, Benzel E, Ellenbogen R, Green BA, Kula R, Menezes A, Mueller D, Oro' JJ, Iskandar BJ, George TM, Milhorat TH, Speer MC.
Phenotypic definition of Chiari type I malformation coupled with high-density SNP genome screen shows significant evidence for linkage to regions on chromosomes 9 and 15. Am J Med Genet A. 2006 Dec 15;140(24):2776-85.
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