Breeds Affected: Corgi
Samples Accepted: Blood, Buccal Swabs
Disease Information: Muscular dystrophy (Duchenne-type) or DMD, is a disorder in which muscle fiber degeneration leads to weakness, a “bunny hop” gait, difficulty opening the jaw, curvature of the spine, and muscle wasting. Affected pups can be identified at 8-10 weeks of age. The disease is fatal.
Inheritance Information: DMD is X-linked recessive, because the DMD gene is located on the X-chromosome.
The possible genotypes are:
XX This dog is a normal female.
XXDMD This dog is a carrier female. She is clinically normal, but will pass the mutation (XDMD) to 50% of her offspring. When bred to a normal male, she can have pups of all four genotypes: normal female (XX), carrier female (XXDMD), normal male (XY), and affected male (XDMDY).
XY This dog is a normal male.
XDMDY This dog is an affected male.
– Female offspring of a carrier female should be genetically tested to determine if they are normal or carriers (XX or XXDMD).
– Carrier females (XXDMD) should not be bred, because affected males can be produced.
– Affected males (XDMDY) should not be used for breeding.
Test Information: This mutation test identifies a LINE-1 insertion in intron 13 of the DMD gene.
Smith, BF., Yue, Y., Woods, PR., Kornegay, JN., Shin, JH., Williams, RR., Duan, D.: An intronic LINE-1 element insertion in the dystrophin gene aborts dystrophin expression and results in Duchenne-like muscular dystrophy in the corgi breed. Lab Invest 91:216-31, 2011. Pubmed reference: 20714321. Doi: 10.1038/labinvest.2010.146.
Further information is available at the Online Mendelian Inheritance in Animals website.