Muscular dystrophy - dystroglycanopathy in Labrador retrievers

Muscular dystrophy type dystroglycanopathy is a genetic disease that affects the muscles and causes their gradual degeneration. Muscle weakness is already evident in puppies, which do not thrive well due to poor suckling. Clinical manifestations also include difficulty in movement, bending sideways, progressive muscle wasting and respiratory problems.

In Labrador retrievers, the disease is caused by the nonsense mutation c.1363C>T in the LARGE gene, which encodes an enzyme involved in the post-translational modification of α-dystroglycan, a protein important for muscle fibre stability.

The mutation shows autosomal recessive mode of inheritance. It means that the mutation will be expressed only in individuals that inherit the mutant allele from each parent (recessive homozygote). A heterozygote is an individual that inherited the mutant allele from one parent and shows no symptoms and is clinically healthy but can pass the mutant allele to its offspring.

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References:

Shelton, G.D., Minor, K.M., Guo, L.T., Friedenberg, S.G., Cullen, J.N., Hord, J.M., Venzke, D., Anderson, M.E., Devereaux, M., Prouty, S.J., Handelman, C., Campbell, K.P., Mickelson, J.R. : Muscular dystrophy-dystroglycanopathy in a family of Labrador retrievers with a LARGE1 mutation. Neuromuscul Disord 31:1169-1178, 2021. Pubmed reference: 34654610