Now Offering VWD3-SCOT, VWD3-SHET, A-a Locus, A-Ay Locus

Von Willebrand’s Disease Type 3 Scottish Terrier (VWD3-SCOT)

Von Willebrand disease (vWD) is a genetic disorder that prevents normal blood clotting and can cause extended bleeding following injury. The disorder results from a deficiency or lack of sufficient von Willebrand factor (vWf) which functions as a binding protein during blood clotting. Three types of vWD have been identified in dogs to date and are known as vWD type 1, 2 and 3. Within these three types there are five different genetic mutations that are currently known that lead to canine vWD. Von Willebrand’s disease type 3 (VWD3) is a very severe form of the disease in which affected animals produce no von Willebrand Factor protein in their blood. This condition makes affected dogs likely to suffer from abnormal and severe bleeding which can lead to life threatening consequences in common minor injuries or surgical procedures.

Von Willebrand’s Disease Type 3 Shetland Sheepdog (VWD3-SHET)

Von Willebrand disease (vWD) is a genetic disorder that prevents normal blood clotting and can cause extended bleeding following injury. The disorder results from a deficiency or lack of sufficient von Willebrand factor (vWf) which functions as a binding protein during blood clotting. Three types of vWD have been identified in dogs to date and are known as vWD type 1, 2 and 3. Within these three types there are five different genetic mutations that are currently known that lead to canine vWD. Von Willebrand’s disease type 3 (VWD3) is a very severe form of the disease in which affected animals produce no von Willebrand Factor protein in their blood. This condition makes affected dogs likely to suffer from abnormal and severe bleeding which can lead to life threatening consequences in common minor injuries or surgical procedures.

A-a Locus (A-a Locus)

The A Locus (agouti series) interacts closely with the E, K, and B Loci that can lead to a dog’s overall coat color and pattern. A Locus mutations are only expressed if the dog is “Clear” or “Carrier” at the E locus and “Clear” at the K-KB locus. There are three potential mutations at the A Locus that can each have a different effect on coat color. The mutations are known as A-ay, A-at and A-a and can determine whether a dog is a Carrier of sable/fawn, black and tan/tricolor/tan points coloration or a recessive form of a solid black or bicolor coat color.
The A-a Locus mutation results in a dog that is solid black. To confirm the source of the black coat, this also requires testing for the K-KB Locus to determine if the black color is derived from the dominant K-KB mutation or the recessive A-a mutation. A common example of the effect of this mutation is typically seen in solid black German Shepherds.

A-Ay Locus (A-Ay Locus)

The A Locus (agouti series) interacts closely with the E, K, and B Loci that can lead to a dog’s overall coat color and pattern. A Locus mutations are only expressed if the dog is “Clear” or “Carrier” at the E locus and “Clear” at the K-KB locus. There are three potential mutations at the A Locus that can each have a different effect on coat color. The mutations are known as A-ay, A-at and A-a and can determine whether a dog is a Carrier of sable/fawn, black and tan/tricolor/tan points coloration or a recessive form of a solid black or bicolor coat color.
The A-ay gene mutation produces a coat color that can range from a light fawn to darker red to a sable based on variation in gene expression. For dogs that are “Clear” at the K-KB Locus and have one or two copies of the A-ay mutation will always express a sable/fawn coat color. This means a dog that appears fawn or sable can carry any of the other A-locus alleles (A-at, A-a or A-aw) and would not express them. The A-Locus alleles are expressed in a hierarchical manner with A-ay being dominant to and expressed over A-aw, A-at and A-a. A-aw is the next most dominant mutation followed by A-at and the least dominant mutation, A-a. It is important to note that the dog’s coat color is also dependent on the dog’s genotypes at E, K, and B Locus among others.