Leg Shortening

cddy chondrodystrophy

cdpa chondrodysplasia

ivdd 

shortening of the limbs is SEMI-dominant so not all dogs with CDDY will have short legs, but having more copies of CDDY or more copies of CDPA increases the likelihood of leg shortening. 

text book example is the dachshund - 2 copies of CDPA and CDDY who have extremely short legs

may be gene variants that contribute to leg shortening that we can't test for yet 

important considerations for those making mini doodles because we are often combining different breeds with significantly different statures and the presence of these mutations can result in a medium to large size dog with very short legs even though the parents may have appeared more proportional 

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Do these genes cause disease?

short legs were selected for over many generations without knowledge that it could contribute to disease.

CDDY is unlike many other genetic diseases we test for because it is not recessively inherited. recessive diseases require 2 copies of the gene variant in order to put the pet at risk. the risk associated with type 1 disc disease is present with only 1 copy of CDDY. 

cddy associated with one type of disc disease type 1

having 2 copies does not result in higher risk than having 1 copy 

what does disc disease look type? spectrum of disease vary from pain to paralysis and even death in severe cases with myelomalacia. treatments can range from medical management with activity restriction to surgery. some pets are euthanized due to the severity of disease. 

just because a dog has 1 or two copies does not mean they will develop signs of disc disease during their life. it is NOT inevitable! for example 

dogs with only cdpa can have short legs but do not appear to be at increased risk of IVDD

dogs with both cdpa and cddy are at the highest risk for ivdd

 approximately 1/4 of dachshunds will develop clinical signs and be diagnosed with IVDD throughout their life. other breeds 5-15x more likely to develop type 1 disc disease when compared to cddy clear dogs. now 5-15x increased risk might sound scary but in some cases we're starting with a very low risk for an individual breed. for example if the risk for a breed is 0.1% of the population will develop clinical signs and we multiply that by 15 approximately, the statistcial risk is still only 1.5% of dogs will develop clinical signs!

it is inaccurate to say that a pet "carries" CDDY because this genetic term only applies to recessively inherited diseases. 

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Breeder's Discussion

prevalence of cddy in toy and mini poodles is very high. approximately _ % of them will have 1 or 2 copies. when working with purebreds, such as the mini poodle, eliminating all dogs with 1 or two copies of cddy from the breeding population at once would be detrimental to the breed and decrease genetic diversity for other important genes and traits. we could be unknowingly selecting for an increase in diseases that we do not have the ability to test for currently.  breed to clear dogs and DNA test puppies prior to selecting your breeding prospects for the next generation. 

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testing - pawprint genetics and animal genetics are more reliable than embark due to the methods of testing. 

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pet peeve - dogs don't "CARRY" CDDY. carrying is a genetic term used for diseases with autosomal RECESSIVE transmission. because CDDY is believed to be autosomal dominant, it is more accurate to say that a dog has 1 or 2 copies of CDDY.