Shaking puppy syndrom (SPS)

Shaking puppy syndrome (SPS or Tremor) is a disease characterized by uncontrollable shaking of the puppies' entire body shortly after birth and often leads to premature death.

The cause of the disease in the Springer Spaniel is a missense mutation c.110A>C in the gene for proteolipid protein (PLP1), one of the main components of myelin. Histidine is substituted for proline and the properties of the resulting protein are altered. The mutation causes a reduction in the number of mature oligodendrocytes forming the myelin sheath in the central nervous system.

The mutation is X-linked. This means that it is localized on the X chromosome. Since the genotype of males is composed of X and Y chromosomes, they can only be healthy (unaffected by the mutation) or affected. The female genotype contains two X chromosomes, so females can be either healthy, carriers or affected. Female carriers do not show clinical signs but are able to pass the mutated allele to their offspring. Breeding of carrier females is not recommended. A genetic test can clearly reveal the genotype of an animal and is a useful tool for breeders to prevent unintentional breeding of affected puppies.

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References:

Nadon, N.L., Duncan, I.D., Hudson, L.D. : A Point Mutation in the Proteolipid Protein Gene of the Shaking Pup Interrupts Oligodendrocyte Development Development 110:529-537, 1990. Pubmed reference: 1723945.