von Willebrand's Disease

Common Symptoms: Von Willebrand Disease I (VWDI) is an inherited bleeding disorder. Dogs affected with VWDI have less than half of the normal level of von Willebrand coagulation factor (vWf), which is an essential protein needed for normal blood clotting. There is variability in the amount of vWf such that not all dogs with two copies of the Mutation are equally affected. Dogs that have less than 35% of the normal amount of vWf generally have mild to moderate signs of a bleeding disorder. Affected dogs may bruise easily, have frequent nosebleeds, bleed from the mouth when juvenile teeth are lost, and experience prolonged bleeding after surgery or trauma. Less often, the bleeding may be severe enough to cause death. Most dogs will have a normal lifespan with this condition despite increased blood clotting times.
NOTE: The levels of vWD:
CLEAR - no mutations/no symptomsCARRIER - 1 mutation/no symptomsAFFECTED - 2 mutations/symptoms
In very early days many dog breeds had their ears cropped to protect them from torn by badgers, otters, weasels, wolves - whatever predators they were used to hunt. These cairns show cropped ears. One cairn is white - these dogs became known as West Highland White terriers.

Important Information About vWD and Breeding

Dog breeding is often described as a art, not a science. This is absolutely true as there are very few "written in stone" guidelines even for ethical, concerned breeders. 
To understand this, consider there are NO perfect dogs. EVERY dog has faults; faults of character, faults of structure, faults of genetics. Knowing this, the talented and ethical breeder must weigh up every dog's pros and cons and take them into consideration when determining if and to whom a specific dog should be bred. 
Some issues must be given more weight than others. Example: poor temperament should be a deal breaker while a minor structural defect such as tail set should be given much less consideration. Every breeding should be considered not as an individual, stand alone event, but as a component of a larger program with far reaching goals. In a perfect world breeders would select as breeding partners dogs which had zero genetic health mutations, but this is not possible. So the careful breeder must weigh together dozens of considerations including which diseases to give priority to avoiding.
von Willebrand's Disease has been surrounded with considerable controversy from its discovery. One of the complicating issues is that the disease presents with a wide range of symptoms from undetectable to life threatening. For the most part however, it should be understood that this disease poses a low risk to individual dogs. This disease can (and should be) eliminated from the breed by carefully selecting away from affected and carrier dogs when possible. 
At this time, vWD seems to be quite rare in cairn terriers, and is only presenting at Level 1. We can stamp it out of the breed - but ONLY if breeders will DNA test their dogs for it!