C112 - Canine Muscular Dystrophy

Canine Muscular Dystrophy is a general term that refers to a large group of inherited and progressively debilitating muscle disorders characterized by degeneration of skeletal muscle. Clinical signs first appear at 6-9 weeks of age and include progressive weakness, stiff gait, muscle atrophy and contractures. Serum creatine kinase (CK) levels are markedly elevated and may be detected as early as 1-2 days of age. Characteristic morphologic lesions are present in muscle biopsies including muscle necrosis, phagocytosis, regeneration, hypertrophy, endomysial fibrosis and myofiber mineralization. Cardiomyopathy has consistently been present in X-linked MD and older dystrophic dogs may die of heart failure.

X-linked recessive inheritance patterns of this disease have been described in Golden Retrievers.

Clinically, the diagnosis of X-linked Canine Muscular Dystrophy is made by demonstrating a marked reduction in or absence of the protein dystrophin by immunohistochemical and confirming by DNA testing. The DNA test is used for the reliable identification of female dogs that do not carry mutant X chromosome. These "normal" females can be bred to any male dog (even to an affected dog), which may be a desirable breeding prospect for other reasons.