Chondrodysplasia
Chondrodysplasia is a genetic disorder in the
Alaskan Malamute which manifests itself in
puppies born with crippling deformities,
eventually evident in the abnormal shape and
length of their limbs. Chondrodysplasia is
present in adult carriers as an auto-somal or
simple recessive gene. Therefore, both sire and
dam must carry this gene in order to produce an
affected (chondrodysplastic) puppy.
As Malamute
owners and prospective owners, we have an
opportunity to control the proliferation of
chondrodysplasia in the Alaskan Malamute, and
with such control, there is hope of it's total
elimination in our breed.
History and Explanation
For a number
of years, Alaskan Malamute breeders in both the
United States and Canada were aware of
occasional litters that contained deformed or
"dwarf puppies", produced by parents who showed
no physical evidence of the condition. It was
not until the early 1970's that these puppies
were conclusively proven to be the manifestation
of a genetic disorder. At first, these affected
dogs were known as "dwarves" because of their
diminutive size. This term gave rise to
considerable confusion. Veterinarians associated
it with the dwarfism found in Hereford cattle,
while owners associated it with any small
Malamute. Since neither is correct, another
name, chondrodysplasia (meaning "faulty
cartilage"), was coined and brought into usage.
Chondrodysplasia in the Malamute was originally
diagnosed as a form of rickets. Upon closer
examination at various veterinary schools, it
was determined that this diagnosis was
incorrect. While it isn't known exactly what
this crippling problem is, it has definitely
been proven to be genetic, or inherited. A more
technical description of this gene is "auto-somal,"
or "simple recessive." This simply means that
the sire and dam must both carry this
gene in order to produce an affected
chondrodysplastic puppy.
In very young
puppies, under six weeks of age, the deformity
is often very difficult, if not impossible, to
detect without x-rays, even to the practiced
eye. But as the puppies grow older, the
deformity becomes more evident in the shape and
length of the front legs. However, not all
chondrodysplastics are severely affected. In
some adults, the front legs may appear "almost"
normal.
It is not the
chondrodysplastics themselves that are
the major problem. The greatest concern is the
use in breeding of the completely normal
appearing dogs that possess or "carry" this
gene. (A good parallel of this among humans is
two brown-eyes parents producing a blue-eyed
baby. In spite of their brown eyes, the parents
both "carry" the gene for the blue eye.) While
the breeding of two carriers can produce a
chondrodysplastic, a litter from a breeding
between a carrier and a "non carrier" (or clear)
will contain only normal appearing dogs.
Nevertheless, an undetermined number of puppies
will themselves be carriers, having inherited
the gene from their carrier parent. The
continued whelping of such litters increase the
number of carriers "at large" in the total
Malamute population.
Chondrodysplasia
Certification Registry (CHD
CERTIFIED Malamutes)
As of January
1, 1993, CHD Certification will be available to
dogs with one certified ancestor between the
applicant dog and each uncertified ancestor
visible within its five generation pedigree. If
proof can be offered that an uncertified ancestor
is a full sibling to a certified dog, the
applicant's pedigree will be evaluated via the
C.C.C. five generation pedigree.
It should be
noted that certification can be revoked when
information is verified that a dog was mis-classified
through subsequent breedings and/or test
breedings.
Certification
is done by checking a five generation pedigree
of the dog. If this examination reveals the
dog's ancestors are certified (or certifiable) a
certificate is issued to that dog bearing an
AMCA number (AMCA-XXXX). Each dog is assigned an
individual number.
Sometimes the
pedigree reveals the dog to be non-certifiable
with regards to Chondrodysplasia. In such cases,
the AMCA recommends these dogs not be bred. The
owner may feel the dog to be a great asset to a
breeding program, or the dog may already have
offspring who are themselves now affected by the
un-certifiable status of the parent. In such
circumstances, the owner may choose to apply for
a further screening process known as "Test
Breeding".
Test Breeding
The committee
will assist the owner in this choice. At
present, test breeding a suspect Malamute to a
Chondrodysplastic, or to a known carrier, is the
only means to be reasonably certain the dog is
not a carrier of the gene. Should the owner
decide to enter the suspect dog into a test
breeding program, a contract specifying certain
criteria is entered into with the AMCA
Chondrodysplasia Certification Committee. The
Committee Chairman and Area Representatives are
available for consultation regarding the
procedures for test breeding.
Once thought
to occur only in Malamute, Chondrodysplasia has
now been detected in other breeds and the AMCA
program has become a model for other breed
clubs. Your efforts are needed if it is to
continue to fulfill its vital leadership role.
We hope you will join us in the fight to control
this genetic disorder.
It is
essential for the prospective malamute purchaser
of potential breeding stock to realize the
importance of these certificates. By purchasing
from AMCA Certified stock, the buyer not only is
helping the breed cull out Chondrodysplasia, but
is also relieving himself of the responsibility
of test breeding.
For more
information or assistance, contact your CCC
Contact.
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