Prekallikrein Deficiency in the Shih-Tzu breed

This is a rare inherited blood disorder. Prekallikrein is a protein that is involved in the early phase of the blood clotting process. Dogs with this disease have increased bleeding, prolonged bleeding after surgery or trauma, bruise easily and often suffer from epistaxis (nosebleeds). The disease in Shih-Tzu is caused by a missense mutation c.988T>A in the KLKB1 gene.

The mode of inheritance of the mutation is autosomal recessive. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. In the case of a mating between two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease.

The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to prevent unintentional breeding of affected puppies.

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References:

Okawa, T., Yanase, T., Shimokawa Miyama, T., Hiraoka, H., Baba, K., Tani, K., Okuda, M., Mizuno, T. : Prekallikrein deficiency in a dog. J Vet Med Sci 73:107-11, 2011. Pubmed reference: 20736516