Limb-Girdle Muscular Dystrophy Type R3 in Miniature Dachshund

Muscular dystrophy is characterized by progressive muscle dysfunction leading to impaired mobility. In this case, the muscles of the limb-girdle, i.e. the muscles of the shoulders and pelvis, are particularly affected. The disease is manifested by a stiff gait and exercise intolerance, and to a lesser extent by swallowing difficulties. Symptoms first appear at about 6 months of age and gradually progress. Affected dogs have high levels of the muscle enzyme creatinine kinase in the blood and excess myoglobin in the urine, indicating muscle breakdown.

The disease is caused by a nonsense mutation c.G224A in the SGCA gene, which encodes sarcoglycan alpha, a component of the sarcoglycan complex important for stabilizing the muscle membrane during contraction.

The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to prevent unintentional breeding of affected puppies.

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References:

Mickelson, J.R., Minor, K.M., Guo, L.T., Friedenberg, S.G., Cullen, J.N., Ciavarella, A., Hambrook, L.E., Brenner, K.M., Helmond, S.E., Marks, S.L., Shelton, G.D. : Sarcoglycan A mutation in miniature dachshund dogs causes limb-girdle muscular dystrophy 2D. Skelet Muscle 11:2, 2021. Pubmed reference: 33407862