Test Detail

Duchenne muscular dystrophy is a progressive myopathy caused by the absence of dystrophin due to variants in the DMD gene. At least two causal variants have been described in the Cavalier King Charles Spaniel and it presents with weakness, muscle atrophy and marked elevation of creatine kinase. It is inherited in a recessive X-linked manner.

Described in the Cavalier King Charles Spaniel. Duchenne muscular dystrophy is also described in other breeds (Golden Retriever, Rottweiler, Cocker Spaniel, Labrador Retriever, etc.), each with its own DMD variant; they should not be extrapolated between breeds.

- Test females related to affected animals to identify carriers\n- Do not breed affected dogs or carrier females\n- Affected males must not be used for breeding\n- In the case of a male puppy with weakness and elevated CK, consider DMD testing\n- Molecular confirmation should look for the two variants described in the breed

The clinical picture and the absence of dystrophin on muscle biopsy guide the diagnosis; molecular confirmation requires identifying the specific variant, which is breed-specific. Two different DMD variants have been described in the Cavalier, so a test that detects only one of them may give false negatives.

1. Walmsley GL et al. 2010. A duchenne muscular dystrophy gene hot spot mutation in dystrophin-deficient cavalier king charles spaniels is amenable to exon 51 skipping. PLOS One. PMID: 20072625
2. Nghiem PP et al. 2017. Whole genome sequencing reveals a 7 base-pair deletion in DMD exon 42 in a dog with muscular dystrophy. Mammalian Genome. PMID: 28028563
3. OMIA:001081-9615. Muscular dystrophy, Duchenne type. Online Mendelian Inheritance in Animals.