Degenerative Myelopathy (DM) is a disorder which affects the tissue of the spinal cord. This generally causes muscle atrophy and degeneration of the nerves beginning in the hind limbs leading to loss of ability to walk. Onset is usually around 8 years of age with loss of walking a year or so later.
An autosomal recessive condition with variable expression between breeds caused by a mutation in the SOD1 gene.