LEMP Rottweiler is a central nervous system disease (also known as white matter disease) affecting Rottweiller. LEMP stands for Leukoencephalomyelopathy.

Dogs with N/N genotype will not have leukoencephalomyelopathy and cannot transmit this leukoencephalomyelopathy variant to their offspring.

Dogs with N/LEMP genotype will not have leukoencephalomyelopathy, but are carriers. They will transmit this LEMP variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% leukoencephalomyelopathy-affected puppies.

Dogs with LEMP/LEMP genotype will have leukoencephalomyelopathy, a progressive neurodegenerative disorder.

LEMP Symptoms

Symptoms of Leukoencephalomyelopathy in affected dogs 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. Symptoms usually appear at animal’s young age.

Genetics
Leukoencephalomyelopathy (LEMP) is caused by a mutation within the gene NAPEPLD. NAPEPLD (N-acyl phosphatidylethanolamine phospholipase D) gene encodes for an enzyme of the endocannabinoid system, important in myelin regulation. Population testing of 200 Rottweilers reveals a carrier rate of 8%.

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.

Rottweiler (LEM) was initially recognised in the US as a cause of chronic progressive ataxia with insidious onset in Rottweilers between 1.5 and 4 years of age. The clinical and pathological characteristics of this disease entity were further defined in subsequent reports originating from Australia, the Netherlands and the UK, which described 16 pathologically confirmed cases (of 22 total cases described in the literature) and suggested an autosomal recessive pattern of inheritance. In these reports, Rottweiler LEM presented as a distinctive neurodegenerative disorder restricted to the lateral and dorsal funiculi of the cervical spinal cord and spinal tracts of the trigeminal nerve, pyramids, caudal cerebellar peduncles, cerebellar medulla and optic tracts that showed a sharp demarcation between abnormal and normal white matter and occasional microcavitation in the centre of the lesion. Clinically, affected dogs exhibit progressive ataxia with hypermetria and subtle postural reaction deficits. Thus far, the ante mortem diagnosis of LEM in Rottweilers has been based on clinical suspicion and the exclusion of other diseases of the cervical spinal cord, e.g., compression/instability, neoplasia and inflammation. To date, there have been no magnetic resonance imaging (MRI) studies or genetic investigations of this disease entity.