Back/Spine Conditions (CDPA, CDDY & IVDD)
last updated November 2024
Retrogenes FGF4, chromosome 12 CDDY and IVDD risk, Chondrodysplasia CDPA
Chondrodystrophy and Intervertebral Disc Disease, CDDY/IVDD, Type I IVDD
Type I Intervertebral Disc Disease (IVDD) is a back/spine issue that refers to a health condition affecting the discs that act as cushions between vertebrae. With Type I IVDD, affected dogs can have a disc event where it ruptures or herniates towards the spinal cord.
This pressure on the spinal cord causes neurologic signs which can range from a wobbly gait to impairment of movement. Chondrodystrophy (CDDY) refers to the relative proportion between a dog’s legs and body, wherein the legs are shorter and the body longer.
There are multiple different variants that can cause a markedly chondrodystrophic appearance as observed in Dachshunds and Corgis. However, this particular variant is the only one known to also increase the risk for IVDD.
LINKAGE TEST
DNA sequences that are close together on a chromosome tend to be inherited together. Because of this, we can use genetic variation surrounding a specific variant (i.e. "linked" to it) to infer the presence or absence of a variant that is linked to a health condition or trait. Linkage tests are not as predictive of your dog's true genotype as direct assays, that are used for most genetic tests.
My Research Notes on Back
more objective study and full trial analysis before including it as a Minimum breed standard requirement.
In dogs, 2 retrogenes on chromosome 12 (12-FGF4 and (18-FGF4)) cause short limbs. In particular, the retrogene 12-FGF4 has also been found to be associated with the presence of calcified discs (IVDD) and an increased risk of disc herniation. (Batcher et al, 2019) In dogs, who are homozygous for the gene defect are more likely to develop disc calcifications compared to heterozygotes or wild-types. Cocker spaniels are at high risk. To date, genetically tested cockers have mainly been homozygous for the defect.
Sources: Retrogene source: Leena Inkilä, Batcher et al, 2019 BSS source: Dogwellnet Other cocker spaniels JTO for the years 2021-2025
Test providers: Movet: (AMS, BSS, FN, prcd-PRA, retrogene) https://www.movet.fi/tutkimusikalima-hinnasto/
Laboklin:
Retrogene package 8294 Chondrodysplasia (CDPA) and -dystrophia (CDDY) (IVDD-risk)
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Informal data collected from CSDB
*7 of these have been determined by producing carrier offspring, with a DNA tested mate.
Data lasted updated 2024