Juvenile Dilated Cardiomyopathy (JDC) is an inherited fatal disease in the young Portuguese Water Dog that is caused by a recessive gene (both parents of a puppy must carry the gene to produce the defect). The sign and symptoms of JDC include sudden or rapid death of a puppy with the average age being 6 weeks to 7 months old (there have been cases reported younger than 6 weeks as well as older than 7 months). Some pups have no physical signs or symptoms and are found dead by their breeder or new owner. Some have a 12 to 48 hour onset with loss of appetite, decreased energy level, vomiting, and difficulty breathing. There is no known cure or treatment at this time.
The exciting news is that after years of research funded by the Portuguese Water Dog Club of America there is now a Linked Marker DNA test available. All breeding stock should be tested, the test results will specify 1-1 probable normal, or 1-2 probable carrier. The only way to breed affected puppies is by breeding a carrier to a carrier. So effectively, breeders can now plan their programs without the worry of furthering this tragic condition.
It is important that all prospective owners discuss Juvenile Dilated Cardiomyopathy with breeders. Ask if it is present in their breeding program or in the genetic lines they are working with. Ask to see the result of of tests for each parent.