Causes of Canine X-Linked Muscular Dystrophy
Canine X-linked muscular dystrophy (CXMD) is a genetic disorder that is caused by an abnormality in a particular location on a particular gene located on the X chromosome. In this disease, certain molecules called cytoskeletal proteins are either absent or are present in insufficient amounts. The cytoskeletal protein most commonly deficient in dogs with CXMD is dystrophin. This is the same protein that is lacking in humans who have Duchenne muscular dystrophy. The genetic abnormality in both people and dogs with this particular disease is caused by the absence of the “Duchenne gene transcript,” which is the portion of the gene on the X chromosome that is responsible for coding the production of dystrophin. Dystrophin and other cytoskeletal proteins are essential to normal muscle function and must be present in sufficient amounts to maintain the structural integrity of muscle tissue. They play a key role in the ability of muscle fibers to contract. When muscles lose their contractile capabilities, they cannot work properly, if they can work at all.
Prevention of Canine X-Linked Muscular Dystrophy
Because CXMD is a genetic disorder, most authorities recommend that responsible breeders remove affected animals and their parents from the breeding population. Some experts also suggest not using the siblings of affected dogs for breeding purposes. Other than close management of breeding practices, there is no reported way to prevent dogs from developing X-linked muscular dystrophy.
Owners of dogs with CXMD should tell the breeder of their pet about its condition, so that the breeder has an opportunity to adjust his or her breeding program appropriately. Breeders cannot take steps to eliminate CXMD from the gene pool unless they are aware that it has shown up in one or more of their puppies.