Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

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What is hemophilia?

Hemophilia is a bleeding disorder.  Affected individuals have blood that won’t clot properly so they are at high risk for abnormal bleeding, even from very minor injuries.

There are two forms of the disease called Hemophilia A and Hemophilia B.  The latter is also sometimes called Christmas Diesase, not for the holiday but for the first patient in whom the disease was described.

Do Aussies get hemophilia?

Yes, but it is rare.

What does having hemophilia mean for my dog?

Your dog will be at risk of having mild to serious bleeding episodes if something happens that damages a blood vessel, even the tiny ones.  How serious an episode will be depends on where the rupture occurred and how rapidly blood is lost.  Bleeding episodes require prompt treatment and your dog’s care should be supervised by your vet.  Affected females are extremely rare since the sire would have to be a hemophiliac and the dam a carrier.  If a female has two copies she is likely to bleed out and die at her first heat.  A hemophiliac dog requires significant amounts of care and expense. An affected dog is unlikely to live a full lifespan.

Is hemophilia inherited?

Yes.  Both Hemophilia A and B are sex-linked disease.  The genes are on the X chromosome and disrupt two different blood clotting factors.  Typically females will carry it and their sons, who have only one X, will be affected.  Healthy female carriers have a normal version of the gene on their other X chromosome.  Females with two copies of the mutated version of the gene are rare as the disease is so serious affected males are unlikely to be used for breeding.

Are there DNA tests for hemophilia?

Yes, but you need to know which type the affected dog has so you will know which test to use for the relatives.

What does hemophilia mean for my breeding program?

Neither affected individuals nor carrier females should not be bred.   Half of a carrier bitch’s sons will be hemophiliac and half of her daughters will be carriers.  If a hemophiliac is identified its dam must be a carrier.  The maternal grand-dam should have a DNA test to determine if she is a carrier; the gene mutates readily.  Test living members of the female line back until you identify a clear individual or no further females are still living.