CRANIOMANDIBULAR OSTEOPATHY (CMO)
Kay McGuire, DVM, MS
Winter 2007, NEWS
We have also recently received a progress report
from Dr, Patrick Venta of MSU on his study of
Craniomandibular Osteopathy (CMO). CMO is
an inherited disorder in Westies in which there
is proliferation of boney growth of the lower jaw
or mandible. There are many misconceptions
among Veterinarians that this disease is a
death sentence to a young Westie. If fact, the
disease is rarely fatal but can cause a great deal
of pain and discomfort to the puppy. CMO
most commonly appears around 4-5 months
of age and the remodeling of the bone in the
lower jaw continues until that pupfs growth
phase stops. Many of these dogs may only be
able to open their mouth an inch or so and are
forced to eat gruels for 4-6 months. Treatment
with corticosteroids or non-steroidal antiinflammatories
are used to help control the pain
of the inflammation. Once the rapid growth of
the puppy is abated, many times they are again
able to open their mouths fully and will act
totally normal. There is usually some residual
boney changes that is life-long but the dog is
able to function normally.
Dr. Venta has developed a new genetic marker
called SINEs (Short Interspersed Nuclear
Elements; these constitute more than 20% of
the genome of humans and other mammals) to
try to determine the genome linkage analysis
of CMO. He anticipates the need to identify
several hundred SINEs to scan all of the canine
chromosomes (these are threadlike strands of
DNA and associated proteins in cells that carry
the genes, and function in the transmission
of hereditary information). To date there are
164 SINE primer sets covering the first 18 dog
chromosomes (there are 78 chromosomes in
the dog). The study has begun by scanning
chromosomes in numerical order looking for
linkage data. All studies to this point have been
done by hand to get a feel for their results. Soon
there will be an automated system in use that
should speed the process.
The CMO study is currently on track of time
deadlines with regard to developing the SINE
markers, but is slightly behind schedule for
testing the markers for linkage of the CMO gene.
Use of the automated SINE genotyping system
should catch up the schedule for coverage of the
entire canine genome. Dr. Venta points out that
timing of finding the linked marker is dependent
upon random chance. There is therefore a 50-
50 chance of finding the gene after screening
only the first half of the genome. Should this
not occur, there may be the need of increased
funding the first half of 2008 to complete the project.
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