Chondrodysplasia is a genetically-determined skeletal disorder that occurs primarily in
the purebred Alaskan Malamute. The purpose of this article is to describe chondrodysplasia
and to outline its relation to the veterinary practitioner.
Background
For a number of years Alaskan Malamute breeders in both Canada and the United States have
been aware of occasional litters which contained deformed or "dwarfed" puppies.
But 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
"dwarfs" because of their diminutive size. This term however gave rise to
considerable confusion with the dwarfism found in Hereford cattle. So another name,
chondrodysplasia, was coined and brought into usage. This disorder, however,
does involve far more than simply faulty cartilage maturation. Perhaps when it
has been fully understood and defined, then a more comprehensive name will be in order.
Inheritability
Chondrodysplasia is transmitted as a simple autosomal recessive trait. Its mode of
inheritance was determined by mating all combinations of unaffected, recessive carrier,
and affected animals, until a total of one-hundred-fourteen (114) puppies had been
produced. Identification of chondrodysplasia as a simple recessive has led to
catagorization of the Malamute into three distinct genotypes.
[reference 1]
- Homozygous dominant - clear of the gene (symbol +/+)
- Heterozygous - recessive carrier of the gene (symbol +/dan)
- Homozygous recessive - chondrodysplastic (symbol dan/dan)
The term "dan" is taken from a concatenation of the words "dwarfism anemia".
d = dwarfism an = anemia
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Linda Dowdy
P.O. Box 137
Bethel, Minnesota 55005
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Copyright © 1999 Linda Dowdy, last revision 991019