Muscular dystrophy, Ullrich type in Labrador Retriever

Ullrich muscular dystrophy is a rare genetic disorder that disrupts the function of collagen VI, which is important for the structural integrity of muscle and connective tissue. Clinical manifestations usually appear in puppies and include mainly muscle weakness and excessive joint mobility.

In Labrador retrievers, two mutations (c.6210+1G>A and c.4726C>T) in the COL6A3 gene have been found to cause this disease.

The disease develops in homozygotes who inherit the same mutation from both parents (P/P), in compound heterozygotes who inherit a different mutation from each parent (P/P compound heterozygote), and in heterozygotes who carry only one mutation (N/P).

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

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Reference:

Bolduc, V., Minor, K.M., Hu, Y., Kaur, R., Friedenberg, S.G., Van Buren, S., Guo, L.T., Glennon, J.C., Marioni-Henry, K., Mickelson, J.R., Bönnemann, C.G., Shelton, G.D. : Pathogenic variants in COL6A3 cause Ullrich-like congenital muscular dystrophy in young Labrador Retriever dogs. Neuromuscul Disord 30:360-7, 2020. Pubmed reference: 32439203.