Overview
Dental hypomineralisation (also called Raine syndrome) in Border Collies is a genetic condition that mainly affects how their teeth form and harden. Affected dogs have teeth that are much softer and weaker than normal, which leads to a range of painful dental problems. Affected teeth are discoloured, typically appear at a young age and as the teeth wear, the sensitive inner part of the tooth (the pulp) can become exposed, causing pain, inflammation and infection. Affected dogs often show signs of discomfort when eating, may avoid hard food or toys, and can develop pulpitis, which causes the tooth to die.
There is no cure, and the only effective treatment for severely damaged teeth is extraction.
The single nucleotide substitution in the gene called FAM20C that causes Raine syndrome/dental hypomineralisation in Border Collies is recessive. This means that dogs that carry two copies of the mutation (homozygotes) will almost certainly develop Raine syndrome during their lives. Dogs that carry a single copy of the mutation (also known as carriers or heterozygotes) will not develop Raine syndrome as a result of the FAM20C mutation, but they will pass the mutation onto about half of any offspring they have. Breeding dogs that will not develop Raine syndrome should be the breeder’s priority, with a reduction in mutation frequency within the whole breed being the secondary, longer-term target.
Carriers can be bred from safely, provided they are mated to a dog that has also been tested and is clear of the FAM20C mutation (i.e. carry no copies of the mutation). If a carrier is mated to a clear dog approximately half of the resulting puppies will also be carriers, so should be tested themselves prior to breeding. Breeding carriers to tested, clear dogs is safe, in terms of avoiding dogs affected with Raine syndrome, and will help to maintain the genetic diversity of a breed. It is therefore encouraged, particularly in the first few generations following the availability of a new genetic test, so that other desirable characteristics and traits can be preserved before the frequency of the disease mutation within the breed is gradually reduced.
