Researchers have recently made yet another breakthrough when they discovered a type of gene mutation that causes deadly heart disease called SAS in Newfoundland dogs.
Subvalvular aortic stenosis, or SAS, is one of the more common congenital heart defects found in dogs. Newfoundlands, Rottweilers and Golden Retrievers have been suffering from this condition for a long time, but it has occurred in other breeds as well. Case of the disease has even been found in children.
However, while a surgery can correct the problem in humans, researchers are yet to find a way how to cure SAS in canines.
Until recently, scientists and veterinarians knew that it was some sort of genetic disorder passed down from one generation to the next, but there was no evidence pointing to what type of mutation caused it, and thus there was very little hope for a cure.
A dog’s heart is divided into four chambers and each chamber is separated by a valve. Those valves work together to ensure that blood only flows one way through the heart.
What is Subvalvular aortic stenosis?
In dogs, Subvalvular aortic stenosis shows up as a ridge or a ring of abnormal tissue in the heart just below the aortic valve. The growth restricts the blood flow from the heart through the aorta. “Subvalvular” refers to the place below the valve – the aortic valve in this case – and “stenosis” is the scientific term for obstruction.
SAS can cause dogs to faint, have an irregular heartbeat, collapse unexpectedly, and it can even cause abrupt death.
There are two forms of Subvalvular aortic stenosis. The mild form will have little effect on a dog and they should be able to live a normal lifespan. But if a dog has the form of SAS that’s more severe, even with medication there’s very little chance that the canine will be able to live past 5 years old.
New scientific data on SAS in Newfoundland dogs
This month, researchers have finally identified the particular gene mutation that is associated with SAS in dogs.
During their research , scientist have studied 93 Newfoundland dogs along with 180 control dogs of 30 different breeds. According to the study which was published in the journal Human Genetics, researchers analyzed thousands of genes in Newfoundland dogs and found that the mutation occurs in the PICALM gene.
Dr. Joshua Stern, a veterinary cardiologist who led the study, says that the same gene mutation is linked to lesions in the brains of people suffering from Alzheimer’s disease.
“Our hope now is that breeders will be able to make informed breeding decisions and avoid breeding dogs that harbor this mutation, thus gradually eliminating the disease from the Newfoundland breed. In addition, now that we know one gene is responsible for SAS and more about which proteins are involved, we can move forward to consider novel therapies that may help treat this devastating condition,” Stern added.
The study is a breakthrough in modern pet medicine, and researchers are hoping that it will help other scientists develop future molecular and genetic inquiries into other heart defects in various species.
They are also hoping that it will help educate breeders and pet owners about the importance of not breeding dogs with such conditions.
Even though it is not passed on to every puppy, it may still be passed to some and it would be irresponsible to breed dogs that could spread such a disease. Not only that, but if people stop breeding dogs with this condition altogether, there’s a chance that eventually Subvalvular aortic stenosis will no longer exist as a condition in canines.
- Stern JA et al. A single codon insertion in PICALM is associated with development of familial subvalvular aortic stenosis in Newfoundland dogs. Hum Genet. 2014 Sep;133(9):1139-48. DOI: 10.1007/s00439-014-1454-0