The PWDCA Heart Committee is concerned with any health condition involving the heart and circulatory system of PWD's. Heart murmurs, congestive heart failure, Tetralogy of Fallot, Pulmonic Stenosis, and Patent Ductus Arteriosus are among the conditions reported to the committee. Juvenile Dilated Cardiomyopathy, JDCM, is a deadly disease found in the breed. It is recessively inherited and causes sudden death in puppies between the ages of five weeks and seven months. Fortunately, this disease no longer presents a challenge for breeders.

In October, 2007, a JDCM Linked Marker Test, to ascertain the JDCM genetic status of our dogs, was developed by researchers at the University of Pennsylvania. Test results were reported for individual dogs as 1-1 Probable Normal (did not carry the marker), 1-2 Probable Carrier (probably did carry the marker, and 2-2 Probable Affected (had the disease).

In September, 2010, these same researchers at the U of PA found the actual gene mutation associated with JDCM and developed a DNA gene based test to determine normal and carrier Portuguese Water Dogs. By having their breeding stock DNA tested, breeders can avoid producing affected puppies by identifying the normals and the carriers. The only way to produce a puppy that would die from the disease would be to breed two carriers together.

The Heart Committee strongly recommends that one of a breeding pair, either the sire or dam, be DNA tested as Normal. This means that a Carrier can be bred – but only to a Normal. The recessive nature of the disease precludes breeding two carriers together as 25% of the litter would be affected with JDCM, thus producing puppies which will die.

The JDCM Test is available through PennGen Laboratories: http://research.vet.upenn.edu/PennGen.

Action Taken By The PWDCA:

The PWDCA is fortunate to have the financial assistance of the Portuguese Water Dog Foundation, in supporting research projects, especially the one which dealt with JDCM. Drs. Meg Sleeper and Paula Henthorn at the University of Pennsylvania are the researchers who developed the Linked Marker Test and then the DNA gene test. Dr. Sleeper is also looking into cases of Pulmonic Stenosis.

The PWDCA and the Portuguese Water Dog Foundation continue to raise funds to support the research projects. The PWDCA Heart Committee continues to provide educational material on heart-related problems through the club's magazine, The Courier. Two 2003 issues provide a complete explanation of JDCM and a visual pedigree showing the progression of the gene through a typical pedigree. Refer to May/June 2003, pages 24-25 July/August 2003, page 34.


Please report all instances of heart conditions in any age Portuguese Water Dog to the PWDCA Heart Committee.

In the event of the sudden, unexplained death of a young Portuguese Water Dog, a correct diagnosis is imperative. Please contact a member of the Heart Committee immediately.

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