Leukoencephalomyelopathy (LEMP)

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A neurological disorder, termed leukoencephalomyelopathy (LEMP) has been described in Rottweiler and Leonberger dogs. LEMP is a recessively inherited neurodegenerative disorder that affects the white matter of the central nervous system (CNS).  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. 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. Like many diseases of the CNS, there is no effective treatment for LEMP. Since in most cases the dog is not in pain, but is strongly restricted in its quality of life, owners are encouraged to ask a veterinarian for advice.

Research carried out at the University of Minnesota, the University of Bern, and Utrecht University has identified two LEMP mutations within the gene NAPEPLD, one in the Leonberger and the other in Rottweilers. The Rottweiler mutation has also been observed in Great Danes.

LEMP in Leonbergers is a partially penetrant autosomal recessive central nervous system disease resulting from an amino acid change within the LEMP gene.  All Leonbergers with confirmed LEMP have tested homozygous affected (D/D) for this mutation; however, not all dogs that are homozygous for this mutation show obvious clinical signs of disease within their lifetime. Clinical signs may develop as early as 1 year of age.

• Population testing of >5,000 Leonbergers indicates that the carrier rate of this mutation is ~14%.

For Leonberger dogs, we also offer genetic testing for three forms of Laryngeal Paralysis & Polyneuropathy (LPN1, LPN2, & LPPN3).

LEMP in Rottweilers and Great Danes is a autosomal recessive central nervous system disease resulting from a 1 base pair insertion within the LEMP gene; clinical signs may develop as early as 1 year of age.  All studied Rottweilers homozygous affected (D/D) for this LEMP mutation have shown clinical signs of disease. However, not all Rottweilers with suspected LEMP have tested affected for this mutation. It is possible that these dogs may be suffering from a different form of LEMP or the other neurodegenerative diseases described in this breed, including - Neuroaxonal Dystrophy (NAD). 

• Population testing of >200 Rottweilers indicates that the carrier rate of this mutation is ~8%.
• Population testing of >250 Great Danes indicates that the carrier rate of this mutation is ~8%.