Degenerative Myelopathy Risk Modifier (DMRM, 5 variants)

Canine Degenerative Myelopathy (DM) is an incurable progressive neurodegenerative disease of the spinal cord. Neurodegenerative diseases are characterized by the progressive loss of neurons in the central nervous system (CNS), leading to functional impairments. In the case of DM, the affected region is the spinal cord, which results in ataxia (a loss of coordination) and paresis of the hind legs. DM is similar in many ways to Amyotrophic Lateral Sclerosis (ALS) in humans.
In Pembroke Welsh Corgi (PWC) a risk modifier has been found in the SP110 nuclear body protein. When present alongside a homozygous SOD1 (DM Exon 2) mutation, this modifier may increase the risk of developing DM and clinical signs will occur at an earlier age.

Most dogs affected with DM begin to show signs at 9 years of age or older. These signs include reduced strength in the hind legs, incontinence, hyporeflexia, spasticity, and pelvic limb ataxia. The disease progressively worsens, eventually leading to complete paralysis.

When one or more SP110 Degenerative Myelopathy Risk Modifiers (DMRM) are present in a Pembroke Welsh Corgi, alongside a SOD1 mutation, clinical signs will likely start at an earlier age.