Leukoencephalomyelopathy is a recessively inherited neurodegenerative disorder that affects the white matter of the central nervous system (CNS) described in Leonbergers and Rottweilers. Canine LEMP is characterized by slowly worsening gait abnormalities, especially spontaneous knuckling, dragging of the paws, and hypermetria of the thoracic limbs, and a characteristic pattern on magnetic resonance imaging (MRI). Affected dogs show corresponding gross lesions in the cervical spinal cord white matter that may extend to the thoracic spinal cord, as well as to the brain; peripheral nerve and muscle biopsies are unremarkable. Canine LEMP often shows a juvenile onset and is characterized by a generalized progressive ataxia. The spinal reflexes of affected dogs are mostly normal. In the progressive clinical course of the disease, affected dogs may become increasingly immobile within a few months.
Together with colleagues from the University of Minnesota, we were able to identify two causative mutations for different forms of LEMP (one in Leonbergers and one in Rottweilers) and offer gene tests for diagnostics. Our studies also indicate that the Rottweiler mutation is present in Great Danes.