Prekallikrein deficiency / Fletcher factor deficiency (KLKB1-related) - Shih Tzu

What does this test analyse?

This genetic test analyses the KLKB1 c.988T>A variant for prekallikrein deficiency / Fletcher factor deficiency in the Shih Tzu. KLKB1 encodes plasma prekallikrein, a protein interacting with factor XI and factor XII in the intrinsic coagulation pathway.

What does this condition mean?

Prekallikrein deficiency affects the contact phase of blood coagulation and is often noticed through a prolonged activated partial thromboplastin time (aPTT) in laboratory testing. The condition is also called Fletcher factor deficiency, PK deficiency or KLKB1-related prekallikrein deficiency. Many dogs show little or no spontaneous bleeding, but genetic status is useful for breeding plans and for interpreting abnormal coagulation results.

Inheritance and result

The trait is inherited as an autosomal recessive condition. Carriers have one copy and can pass the variant on. Dogs with two copies have the genotype that causes prekallikrein deficiency.

Practical value of this test

• Helps breeders identify carriers and avoid carrier-to-carrier matings.
• Adds valuable context when a dog has prolonged aPTT in coagulation testing.
• Distinguishes inherited prekallikrein deficiency from other causes of abnormal clotting tests.
• Supports careful planning in lines where coagulation-factor abnormalities occur.
• Documents variant status clearly for breeding advice, sale information and future combinations.