Health Condition

Storage Disease (GM1 gangliosidosis) is a recessive, genetic disorder. It is produced only when two carriers are bred together. The disorder is caused by a lack of an enzyme that allows the build up of toxic substances in the nerve cells.  It is fatal to affected puppies.

Action Taken by the PWDCA

The PWDCA sponsored testing and research at the Neurogenetics Laboratory of New York University to find the defective gene responsible for GM1. Now that this has been isolated and a definitive gene test developed, the club provides simplified information and applications for this DNA test. The club guideline is for all breeding dogs to be tested unless an AP rating has already been provided. An AP rating was based on the use of the blood assay test through several generations of a dog. It is no longer issued.

Why the PWDCA is Addressing This

GM1 can be fatal to puppies produced by two carriers.

How the PWDCA is Addressing This

After many years of using the available blood assay test that helped provide a 95% to 99% accuracy in determining carriers, a DNA test was developed and has been in use since September, 1999.  Dogs are now DNA tested and found to be either "Normal" or "Carrier". If a Carrier is bred, it must be to a Normal so that no affected puppies will be produced.

A GM-1 Coordinator is responsible for educating PWD owners and breeders on Storage Disease.  The activities to accomplish this include:  maintaining the protocol for the GM-1 testing procedure; updating and modifying the test form as needed; keeping all information current on the PWDCA Web site (coordinating with the Web Master); and providing information on PWD test ratings and the qualifying criteria for those ratings.

The coordinator acts as the liaison between the NYU testing laboratory and the PWDCA and maintains a copy of the GM-1 database with updates of new test results as reported by NYU.  The coordinator has the responsibility of issuing duplicate certificates on behalf of the Club upon verification with the database.

The PWDCA only accepts GM-1 results from NYU.

Current Status (as of August 2006)

By following the breeding guidelines, the threat of producing an affected puppy is statistically very low. The number of carriers has been significantly reduced.

From Aug of 1999 through August 2006 a total of 1200 Portuguese Water Dogs have been tested. 20 (less than 2%) have been identified as "Carriers", no affected puppies have been produced

Other Important References - articles, books, websites

GM-1 Test Instructions and Application Form

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Last Edited: January 22, 2008