Diagnosis of degenerative myelopathy in a Boston terrier-French bulldog mixed breed

Canine degenerative myelopathy (DM) has been associated with mutations in the superoxide dismutase 1 gene (SOD1). Although the SOD1:c.118G>A mutation has been identified in Boston terriers and French bulldogs, no histological-confirmed degenerative myelopathy has been reported in either breed. An 8-year-old male neutered Boston terrier-French bulldog mixed breed dog was presented with T3 to L3 myelopathy. Magnetic resonance imaging (MRI) of the spinal cord and cerebrospinal fluid analysis were unremarkable. DNA testing revealed homozygosity for the SOD1:c.118G>A mutation. Despite supportive treatment, the dog continued to progress over 37 months. Post mortem full spine MRI study found severe spinal cord and epaxial muscle atrophy. The diagnosis of DM was confirmed by histopathology and positive immunohistochemical staining with anti-SOD1 antibodies. This case report documents the clinical and imaging progression of DM in a Boston terrier-French bulldog mixed breed.