Leukoencephalomyelopathy Leonberger Type (LEMP)
Leukoencephalomyelopathy Leonberger Type (LEMP) is a degenerative disorder of the central nervous system in Leonberger dog breed. Except in Leonbergers, disorder has been described also in Rottweilers, but in this dog breed the LEMP is caused by a different causative mutation. Similar diseases with similar symptoms have been recognized in Afghan Hounds, West Highland white terriers, miniature Poodles, Dalmatians, Jack Russell terriers and fox terriers. Similar disorder has been observed in human patients, and identification of a causative mutation of LEMP in Leonbergers reveals a novel candidate gene for human myelin disorders.
Leukoencephalomyelopathy Leonberger Type (LEMP) Symptoms
Symptoms of Leukoencephalomyelopathy in affected Leonbergers include: inability to control bodily movements, inability to judge distance, generalized muscle weakness, hypermetria, and exaggerated spinal reflexes. Neuronal examination revealed myelin breakdown, followed by swelling of the axons.
Due to the progressive derogative nature of the disorder, affected dogs are usually euthanized.
Leukoencephalomyelopathy Leonberger Type (LEMP) is caused by a mutation within the gene NAPEPLD located on the canine chromosome 18. NAPEPLD (N-acyl phosphatidylethanolamine phospholipase D) gene encodes for an enzyme of the endocannabinoid system, important in myelin regulation. Population testing revealed a high carrier rate of ~15% among >7000 tested Leonbergers.
The disorder is inherited in an autosomal recessive pattern. Healthy parents of an affected puppy are obligate heterozygotes, and therefore carry one mutant allele. Heterozygotes have no symptoms. Dogs homozygous for the mutation will display the symptoms of the LEMP. At conception, when mating two carrier dogs, each cub has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.
Oevermann, A., Bley, T., Konar, M., Lang, J. and Vandevelde, M. (2008): A novel leukoencephalomyelopathy of Leonberger dogs. Journal of Veterinary Internal Medicine, 22: 467–471. doi:10.1111/j.1939-1676.2008.0068.x
Minor KM, Letko A, Becker D, et al. (2018) Canine NAPEPLD-associated models of human myelin disorders. Scientific Reports 8, Article number: 5818. doi:10.1038/s41598-018-23938-7