Cardiac Laminopathy (CLAM) in the Nova Scotia Duck Tolling Retriever

Cardiac Laminopathy (CLAM) is caused by a deletion in the LMNA gene (p.Asp576ThrfsTer124). The condition appears to be inherited in an autosomal recessive manner, meaning that two copies of the CLAM variant are needed for the disease to be expressed. Affected dogs are homozygous for the variant and present with sudden death associated with dilated cardiomyopathy. No treatment is available at this time and the condition is typically lethal in young adult dogs. Affected homozygous dogs studied to date experienced sudden death before 2 years of age. 

The genetic variant causing this disease was discovered by Dr. Danika Bannasch here at UC Davis, in the School of Veterinary Medicine. Dr. Bannasch shared her findings with the VGL pre-publication so that we could more rapidly offer genetic testing to toller breeders. The recently published study also described a single heterozygous dog that experienced sudden death at 5 years of age. The dog presented with myocardial fibrosis (scarring of the heart muscle) suggesting that the presence of one copy of this LMNA deletion may also lead to cardiac abnormalities, although no other affected heterozygous dog has been identified to date.

Testing recommendations: DNA testing for cardiac laminopathy can determine the genetic status of dogs. Dogs with one copy of the CLAM variant are normal but are carriers. Matings between two carrier dogs may, on average, produce 25% of puppies with cardiac laminopathy, which is a lethal condition in young adult dogs.