Fanconi DNA Test


Direct Fanconi Syndrome DNA Test FAQ

Prepared by the Health and Research Committee and approved by the BHE Board of Directors in 2011

 

The most common inherited lethal disease in Basenjis is Fanconi Syndrome, a kidney defect that does not become apparent until the dog is old enough to have had offspring.  In 2007, researchers developed a linked analysis test to identify which dogs were likely to develop or pass on the Fanconi gene mutation.  In August 2011, Dr. Gary Johnson DVM PhD and Fabiana Faria of the Department of Veterinary Pathobiology at the University of Missouri, Columbia MO discovered the specific DNA mutation that identifies the Fanconi Syndrome gene.

 

The direct DNA Fanconi Test is currently available from the Orthopedic Foundation for Animals (OFA) and replaces the Fanconi Linked Marker Test.  Results from the Fanconi Linked Marker Test will remain on the OFA website until the dogs are retested, and are indicated with the qualifier, "Probably" before the results "Clear/Normal," "Carrier," or "Affected."  If a dog is retested, the direct DNA Fanconi Test results will replace the Linked Marker Test results, and will not have the word, "Probably."  The DNA Fanconi Direct Test does not have an "Indeterminate" result, as this was only necessary in the Linked Marker Test, when the markers did not clearly indicate the status of the dog.

 

Dr. Johnson provided a version of the powerpoint he presented at the 2011 Basenji Club of America National Specialty with some explanatory notes for use by the BCOA.  Click here to access Dr. Johnson's presentation.

 

Click on questions below for a brief Q&A regarding the direct DNA Fanconi test.

 

1. Who should test and Why?
2.  How do I test my basenji?

 

3.  If my dog has been tested with the linked test, does it need to be re-tested with the direct test?

 

4.  How do I order a re-test on an animal previously tested?

 

5.  Can frozen semen be tested for Fanconi?
6.  What do the test results mean?
7.  What does Fanconi test status mean to breeding decisions?
8.  What should I do if I get an anomalous Fanconi test result?
9.  Should I spay or neuter my dog based on the results?
10. My basenji tested as a carrier with the new direct Fanconi syndrome test.  Should I continue to strip test his/her urine for glucose?

 


1. Who Should Test and Why?

 

Responsible breeders test all potential breeding stock before breeding decisions are made and will share the results and implications of the results with puppy buyers. Owners should want to know their dog’s Fanconi gene status as part of a general veterinary health program. The direct DNA Fanconi Test can reveal the potential for disease before the onset of symptoms.  Early detection and treatment may extend and improve the quality of an affected dog's life.  Owners should contact their breeder for this information and are encouraged to test their own dogs if they have not already been tested as puppies, or are not first generation “OFA Clear by Parentage”.  Owners of dogs for which direct DNA test results of both parents are unavailable (such as rescues) are strongly encouraged to have their dogs tested.

 

This direct DNA Fanconi test is offered only through the Orthopedic Foundation for Animals.  The OFA has an “OFA Clear by Parentage Policy”.  For direct mutant gene tests only, such as the direct DNA Fanconi test, the OFA will issue clearances to untested offspring. Because of the possibility of new mutations or as of yet undiscovered gene mutations, only first generation offspring will be issued clearances under the following circumstances :

If the sire and dam have both been DNA tested “Clear,”
If the sire and dam’s DNA disease test results have been OFA registered, and
If all three (sire/dam/offspring) have been DNA identity profiled and parentage verified.

For additional details, please review the OFA policy on the OFA website. www.offa.org

 

2. How do I test my basenji?

The direct Fanconi DNA test is available through the Orthopedic Foundation for Animals (OFA).  Blood samples are no longer required for DNA extraction, rather cheek swab material is spread on a FTA (Fast Technology for Analysis of nucleic acids) sample collection card by the owner. The cheek swab collection procedure allows for testing at any age, decreases the possibility of human specimen handling error, yields enough DNA for over 30 tests, and samples can easily be sent internationally.  The collection procedure is safe, non-invasive, and can be done at home by the owner; no veterinary appointment is necessary. Directions for how to use the cheek swabs are included in the test kits, and can be reviewed here http://www.offa.org/dnatesting/ftacardproc.html.

Complete instructions on how to order the test can be found here:  http://www.offa.org/dnatesting/fanconi.html.

PLEASE NOTE that there are two Fanconi testing options on the OFA website.  The first, "Fanconi DNA," is for dogs who have not been previously tested with the Linked Marker Test, and is $65.  The second, "Fanconi Retest," is only for dogs who have been previously tested with the Linked Marker Test, and is $50.  The Basenji Health Endowment is subsidizing each retest by $15.  Be sure the registration number, name, and birth date on the retest match that on the original Linked Marker Test certificate.

Upon completion of the online order for the Fanconi Retest of a dog that was previously tested with the Linked Marker Test, the lab will check the storage facility for existing DNA. If enough DNA remains, the test will be performed from the existing sample, whether from blood or a previously submitted FTA card.  A new FTA kit will be mailed where DNA quantities are insufficient.

Certificates will be sent to the owner, and  results displayed on the OFA website. Test result for the DNA Fanconi direct test will not contain the word "Probably" and there will be no "Indeterminate" results.

 

3. If my dog has been tested with the linked test, does it need to be re-tested with the direct test?

If you are going to breed your dog, you should re-test your dog with the direct DNA Fanconi test.  If you have bred to an animal previously tested with the Linked Marker Test, you should re-test the animal to confirm the prior results.  Because any Linked Marker Test has an inherent possibility of mis-classification, all animls that have been bred or will be bred should be retested with the direct DNA Fanconi Test.

You may want to retest even if you never intend to breed your animal to confirm the animal’s true Fanconi Syndrome gene status.

 

4.  How do I order a re-test on an animal previously tested?

You may order a re-test through the OFA website.  Please see Question #2.

 

5. Can frozen semen be tested for Fanconi?

The lab at the University of Missouri can extract DNA from semen, but they need to use two semen straws, and they still may not get usable DNA.  Download handling instructions at www.canine-epilepsy.net/forms.html.

Alternatively, a breeder could use untested frozen semen from a deceased sire, provided the bitch has tested Clear/Normal.  Keep in mind that if the semen donor were Affected, all puppies would be expected to be Carriers.  (see below)

 

6. What do the test results mean?

Each Basenji is genetically either a Clear/Normal, a Carrier, or an Affected for Fanconi Syndrome.

Normal:
This status indicates that the dog does not have a mutated Fanconi gene; the Fanconi  genes inherited from both parents do not contain the mutation. This dog will not get sick from inherited Basenji Fanconi Syndrome, and cannot pass on the mutated Fanconi gene.

Carrier:
This status indicates the dog has inherited a mutated Fanconi gene from one of its parents, and a normal Fanconi gene from the other parent. This dog will probably never develop clinical Fanconi syndrome, as illness generally results only when two mutated Fanconi genes are inherited, one from each parent.  This dog can, however, produce the disease in offspring if bred to another Carrier, or to an Affected.

Affected:
This status indicates the dog has two copies of the mutated Fanconi gene, one inherited from each parent. This result does not mean the dog is sick at this time.  However, dogs with an  "Affected" test result are at a high risk of developing Fanconi Syndrome at some point in their lives; owners need to be especially vigilant, watching for the first signs of the disease.  The earlier the disease is caught and treated, the easier it is to manage and the better the prognosis for a long healthy life.

Note: If your dog is tested as Affected, you should start strip testing your dog’s urine for glucose at every two weeks when they become 1-2 years old, and continue to test regularly for the remainder of their life.   Print out the latest Fanconi information and take it to your veterinarian so that he/she is prepared long before the information is actually needed.  You may also ask your vet about doing a venous blood gas test, as this test can indicate the onset of the disease even before glucose is found in the urine.  If the venous blood gas test is abnormal, you may want to begin treatment.  If the venous blood gas test is normal, plan to continue strip testing your dog’s urine for glucose and ketones every two weeks and recheck the venous blood gas every six months.  Giving a daily nutritional supplement and using filtered water (Basenji Fanconi Syndrome is a kidney disease) are also recommended.  Many dogs with the disease have lived long good lives with treatment.  LINK to Fanconi Treatment protocol.

You might want to join a Fanconi support group for owners of affected dogs such as:

HYPERLINK fanconidogs-subscribe@yahoogroups.com

HYPERLINK http://www.basenjicompanions.org/health/fanconi/index.html

HYPERLINK http://www.basenjiforums.com./index.php.  Under this subhead are a room for Fanconi information open to the public and a support group for owners of Fanconi affected dogs.  Contact admin@basenjiforums.com for access as it is a closed/private group.

 

7. What does Fanconi test status mean to breeding decisions?

Our goal as responsible stewards of the basenji breed is to eliminate Basenji Fanconi Syndrome as an inherited disease without losing valuable genetic diversity.  Breedings that have the potential to produce Fanconi affected offspring are strongly discouraged. Before any breeding takes place, both parents should have been tested, and one parent should have tested Clear/Normal.  When using frozen semen from a deceased, untested sire, the dam should have tested Clear/Normal.

 

8.  What should I do if I get an anomalous Fanconi test result?

If the result does not fit within the range of results that can be expected from your dog’s parentage, (see previous paragraph, “What Does Fanconi Test Status Mean to Breeding Decisions”) notify Dr. Johnson's laboratory and also any member of the BCOA Health and Research Committee.  An example of anomalous results would be when offspring are not within the genetic possibilities of the breeding as listed above, such as Carrier or Affected offspring from two Clear parents, or Affected offspring from a Clear and a Carrier parent.  It is NOT anomalous when 100% of a litter from of a Carrier and a Clear are Carriers.  Although the average percentage, over many offspring, is 50% Carriers and 50% Clears, both Clears and Carriers can be expected from the breeding.  The results are not, therefore, anomalous.  Another type of anomalous result would be a dog that tested Clear or Carrier but later becomes clinically affected, i.e. either sick, or spilling sugar in a urine strip test.   Also of interest are dogs that test Affected but live to an old age without becoming clinically ill.  Self-reporting of anomalous results are extremely helpful in furthering our understanding of Fanconi Syndrome.  Openness and cooperation are needed to eradicate this disease, and as a steward of the breed, you will be helping the fancy.

Notify Dr. Johnson's laboratory email or phone 573-884-3712 to report anomalous test results.

 

9. Should I spay or neuter my dog based on the results?

Spaying or neutering will not change or influence the genetic Fanconi status of your dog. If you are not planning to breed your dog, you may want to consider spay/neuter as you would for any loved companion in your home.

 

10. My basenji tested as a carrier with the new direct Fanconi syndrome test.  Should I continue to strip test his/her urine for glucose?

It is unlikely that carriers of the mutation are at any significant risk of developing Basenji Fanconi Syndrome, but at this time all the mechanisms for expression have not been fully explored. Therefore, it becomes a personal decision as to whether or not urine strip testing is worth the time and expense.


Click here for further information about the Fanconi Linked Marker Test used from 2007 to 2011.


 

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