Shaking Puppy Syndrome (SPS) in the English Cocker Spaniel

Shaking Puppy Syndrome (SPS, also known as Tremor) is a disease characterized by uncontrollable tremors of the whole body, motor dysfunction, and significantly slowed growth. Clinical signs are apparent in puppies from birth, and the disease often leads to premature death.

The cause of SPS in the English Cocker Spaniel is a missense mutation c.92T>A in the gene encoding proteolipid protein (PLP1), one of the major components of myelin. Hypomyelination and a reduced number of mature oligodendrocytes in the central nervous system are the main pathological features of the disease.

The mutation is X-linked, meaning it is located on the X chromosome. Since males have an XY genotype, they can be either healthy (unaffected) or affected. Females, with two X chromosomes, can be healthy, carriers, or affected. Carrier females do not show clinical signs but can pass the mutated allele to their offspring. Breeding of carriers is not recommended. Genetic testing can clearly determine the genotype of an animal and is a useful tool for breeders to prevent unintentional breeding of affected puppies.

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Reference:

Gutierrez-Quintana, R., Montague, P., Rupp, A., Leeb, T., Penderis, J., Byrne, N., Gonzalo-Nadal, V., August, B., Mullin, M., Barrie, J., Edgar, J.M., Duncan, I.D., McLaughlin, M. : A canine PLP1 missense variant differentiates oligodendrocyte maturation in connatal and classical Pelizaeus-Merzbacher disease. Proc Natl Acad Sci U S A 123:e2523008123, 2026. Pubmed reference: 41701830