Glycogen storage diseases are caused by a deficiency of certain enzymes and result in failure of normal glycogen release from the cell. Therefore, glycogen accumulates within the liver and other organs and is unavailable for conversion to glucose.  Glucose is a major source of energy for the body; it is stored in the form of glycogen and later released with the help of enzymes.

Curly-coated retrievers can be affected by glycogen storage disease type IIIa (GSDIIIa); an inherited metabolic disorder that causes liver and skeletal muscle disease due to deficiency of the glycogen debranching enzyme (GDE) and tissue storage of abnormally structured glycogen.   The curlies known to be affected with GSDIIIa have had clinical symptoms consisting of exercise intolerance, lethargy, prolonged recovery from exercise and collapse.  In addition, blood chemistries performed on these curlies have shown elevated liver values beginning when the dogs were under a year of age.  Ultrasound examinations have demonstrated enlarged livers.  Liver biopsies have confirmed abnormal glycogen accumulation. 

In curly-coated retrievers, GSDIIIa results from a single mutation in the glycogen debranching enzyme gene.  This disease is an autosomal recessive trait.  There is a DNA test available to test for the presence or absence of the abnormal gene.  Affected curlies will inherit two copies of the gene from their parents while carriers inherit only one copy of the gene.  Curlies clear of GSDIIIa will have no copies of the abnormal gene.  To date, affected littermates have been identified in the United States and carriers have been identified in the U.S., New Zealand, Canada and Finland. 

The purpose of this web page is to maintain a list of curlies that have been tested for GSDIIIa and to provide a public list of those results.  The information can be used as part of a breeding program to reduce and eventually eliminate GSD in curly-coated retrievers.    Inclusion on the site under "CLEAR," "CARRIER," or "AFFECTED" is voluntary and requires that you send an e-mail with your dog's registered name and test result and test number to the e-mail contact below.  Alternatively, the publicly available results that have been submitted to OFA/CHIC will be reflected in this list. 

Curlies whose parents have BOTH been tested and are both "CLEAR" can also be listed under "CLEAR" because the offspring of a known clear sire and clear dam will not carry the gene for GSDIIIa. 

Many curlies should be considered to be potential carriers of GSDIIIa.  Curlies related to known affected and carrier curlies may not be available for testing because they are no longer alive.  Until we know more about the extent of the disease in curlies, the best recommendation for reducing and eliminating GSD in curlies is to breed only to those dogs with known "CLEAR" or "CARRIER" status.  Carriers can be bred to clear individuals without risk of producing an affected curly but all resulting offspring should be tested to determine which are carries.  Carriers should not be bred to other carriers as this combination can result in affected offspring.