Fanconi Syndrome

 

Fanconi syndrome is a late-onset kidney problem that, at the time of discovery of the DNA test, was determined to occur in approximately 7% of all Basenjis. The incidence since then appears to be dropping rapidly. Untreated, the problem is fatal; with treatment, which consists of bicarbonate and other supplements, dogs with the disorder have a nearly normal lifespan.

 

A DNA test, which looks at multiple markers, has been developed, and is being used extensively until September 2011. While the test was not infallible, dogs with at least one parent tested “Probable Clear” of Fanconi appear to be very unlikely to develop the disease.
In September 2011 Dr. Gary Johnson has identified the mutation responsible for recessive basenji Fanconi Syndrome. To be able to differentiate the new direct test results from the Linked Marker test results, the new direct test will be resulted as Clear, Carrier or Affected.  The term “probably” will no longer appear on the certificate.

 

Fanconi is a disorder in which the kidney does not properly reabsorb electrolytes and nutrients back into the body, but instead "spills" them into the urine.
Symptoms include excessive drinking (polydipsia), excessive urination (polyuria), and glucose in the urine (glucosuria.) If Fanconi is left untreated, muscle wasting, acidosis, and poor condition will also occur.

 

The onset of inherited Fanconi is typically between four and eight years of age, although onsets as early as three years and as late as ten years have occurred.
Untreated, a Basenji with Fanconi syndrome will generally die from the disorder. If caught early and put on the treatment protocol, affected Basenjis can do well. Studies indicate that dogs on the treatment protocol have a lifespan statistically similar to unaffected dogs.

 

For the owner
Owners should insist that at least one parent of any puppy they purchase be tested “Probable clear” for Fanconi, unless the pup itself has been individually tested and was not tested “Probable Affected.” While not a guarantee of health, studies to date indicate that dogs with one or both parents tested probable clear are very unlikely to develop the disorder.

 

For Breeders
Breeding stock should be DNA tested for Fanconi. The linkage marker DNA test for Fanconi is available through the Orthopedic Foundation for Animals at www.offa.org and all test results are in the searchable open database on that site.
The test can determine if a dog is a carrier, clear, or affected with a high degree of accuracy, and can predict that a dog will become affected prior to the development of symptoms.
Any planned Basenji litter should have at least one parent that tests probable clear, to minimize the chance of producing affected puppies.

 

Treatment
In 1990 Dr. Steve Gonto developed a treatment protocol for dogs with Fanconi, based on the treatment human Fanconi patients receive. The protocol uses dietary supplements for acid neutralization and replacement of lost electrolytes and nutrients. This is accomplished with bicarbonate and other supplements in specified doses to re-establish the body's acid-base balance and keep electrolytes at appropriate levels. Dr. Gonto was given lifetime membership in the Basenji Club of America in recognition of the importance of his work.

The Gonto protocol was studied and validated for the veterinary literature by Jennifer Yearley, DVM, while she was completing her professional studies. This was an important step in expanding the awareness of the treatment. The protocol has been very successful in improving both quality and length of life for Fanconi-affected Basenjis. The disorder can be controlled by the protocol, but it cannot be cured.

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Thyroid problems

 

Hypothyroidism is known to occur in Basenjis. The most common symptoms include weight gain, poor coat, reduced activity level, and irritability. Other symptoms, i.e., weight loss have been described. The Orthopedic Foundation for Animals reports that, of Basenjis tested, at the time of this writing, 82.9% were normal in all respects, 6% had autoimmune thyroiditis, 0.4% had idiopathic hypothyroidism, and 10.8% were equivocal. Autoimmune thyroiditis is known to be inheritable.

 

For the owner
Hypothyroidism is easily treated with an inexpensive thyroid supplement; the dose may need periodic adjustment, and this should only be done with veterinary supervision.
Pet owners may want to have their vet periodically check their dogs, especially if they show any symptoms that suggest hypothyroidism.
Thyroid panels test only for current thyroid status. They cannot predict future changes, and they do not indicate if a dog can produce offspring with hypothyroidism.

 

For breeders
It is a good idea for breeders to periodically check their breeding stock with a full thyroid panel beginning in early adulthood. The Orthopedic Foundation for Animals has an open registry for dogs that have been tested for autoimmune thyroiditis at 12 months or older, using approved labs (only for USA). This thyroid test is part of the CHIC panel for Basenjis.
Testing for breeding stock is done primarily to rule out autoimmune thyroiditis, which is known to be inheritable. A full thyroid panel is used, one that includes total thyroxine (T4), thyroid-stimulating hormone (TSH), free T4 by dialysis, and thyroglobulin autoantibody (TgAA or TAA.)
Elevation of both TSH and TgAA levels are used to diagnose autoimmune thyroiditis - however, as the disease progresses, these levels may decrease due to complete destruction of the thyroid gland. Dogs that have had autoimmune thyroiditis for several years but have never been tested might not show the elevated TSH and TgAA needed for definitive diagnosis.

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Hip Dysplasia

 

Hip dysplasia is a hereditary condition in which the hip socket is badly formed, often leading to lameness and arthritis. It is believed to be polygenic, with multiple genes involved in its expression. Approximately 3 - 3.5% of Basenji x-rays submitted to the Orthopedic Foundation for Animals (OFA) are dysplastic.
 

For the owner
When purchasing a puppy, the parents should have been tested for hip dysplasia, and the x-rays should have been read by the Orthopedic Foundation for Animals (OFA) or  competent institution in your country. In Croatia this means the Veterinary Faculty in Zagreb and the veterinary facilities that possess a valid license.

 

For breeders
Breeding stock should be x-rayed for hip dysplasia. The Orthopedic Foundation for Animals has a web site that permits downloads and searches of dogs that have passed with a grade of Fair, Good, or Excellent. In addition, the OFA has recently added the option of having results placed in an open health registry, so that Borderline and Dysplastic ratings can be made public (only for USA).
Good and Excellent are the preferred grades for breeding stock, although Fair is not considered dysplastic. OFA status at 2 years of age is generally considered definitive of that dog's hip status. However, there is a small chance a dog can go dysplastic later in life.
For permanent results, dogs can be X-rayed for hip dysplasia at 2 years of age or older, with the films reviewed by the OFA for the definitive reading. Dogs can be x-rayed earlier for preliminary results if they are being bred prior to 2 years of age.
Breeding from tested normal stock, and using vertical pedigrees to consider the scores of relatives are the recommended methods of controlling hip dysplasia.

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Persistent Pupillary Membrane (PPM)

 

Persistent Pupillary Membrane is a condition where the fetal membrane of the eye does not completely reabsorb. It is a minor and normally benign disorder that is extremely common in Basenjis. Based on CERF statistics through 2006, about 77% of all Basenjis have some PPM as puppies, with about 70.5% having the mildest form – a form that is permitted in dogs certified by the Canine Eye Registration Foundation and is generally agreed to have no affect on quality of life or vision. Of the remaining 6.5%, about 1.8% have sheets as puppies, the more severe form that can cause visual blurring.
PPM does not progress, and in fact often puppies with mild PPM have it reabsorb and disappear completely as they age. For this reason PPM can get better, and it does not get worse.

 

For the owner
Most PPM has no effect on a dog’s life. PPM severe enough to cause visual problems is normally visible to a non-specialist vet, but PPM that severe is extremely uncommon.

 

For breeders
While most PPM does not have a negative effect on a dog’s life, severe PPM can. Severe PPM is now quite rare in Basenjis, but it was more common early in the breed’s history. Breeders were able to successfully breed away from it.
To prevent severe PPM from becoming common again, it is a good idea for breeders to have an ACVO certified veterinary ophthalmologist check their puppies at 7-9 weeks of age, to determine the presence or absence of PPM. All breeders should be aware of the PPM status of their dogs.
A Basenji with iris to iris PPM can receive a Canine Eye Registration Foundation certificate. All other grades of PPM (iris to lens, iris to cornea, and iris sheets) cannot. Most Basenji breeders will not disqualify a dog from breeding solely due to mild PPM. A CERF exam will show current PPM status, but it does not tell you whether or not the dog can produce offspring with PPM.

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Basenji Retinopathy / Progressive Retinal Atrophy

 

Basenji retinopathy, or progressive retinal atrophy (PRA) is an eye condition in which the retina begins to deteriorate later in life, causing night blindness and, if the dog lives long enough, causing deterioration of day vision that can lead to blindness. Onset as diagnosed by specialist eye exam varies, typically between ages 4 and 10, although some cases have been reported between as early as age 3 and as late as 13. Based on Canine Eye Registration Foundation Statistics through 2006, approximately 25% of Basenjis age 8 and older showed signs of retinal changes, although most changes were characterized as PRA suspicious rather than PRA affected. Not all of those dogs have hereditary eye disease, as retinal changes may be acquired or may be due to other disorders.
It is not currently known if Basenji PRA is one disease or more than one. Mode of inheritance is presently unknown.
Basenjis can also have some unusual, but benign, forms of retinal pigmentation that can easily be confused with PRA or retinal degeneration. Both false positives and false negatives are common with Basenji PRA.

 

For the owner
Most Basenjis diagnosed with retinopathy show little change in behavior until very late in life. Reduced vision in low light tends to occur first, typically in mid to late life for affected dogs. Daytime visual deficits do not tend to occur until late in life for most affected dogs. There are rare exceptions that go blind in mid-life. Blindness before mid-life is extremely rare. This is primarily a disease of older dogs, and one in most cases with very subtle symptoms until very late in life.

 

For breeders
Although retinopathy has limited effect on the quality of life for most affected dogs, it is a serious disorder that must be considered in breeding. Because dogs rarely show any sign of the disease until mid-life, an affected dog may be bred prior to diagnosis. Without specialist exam, affected dogs often go undiagnosed throughout their lives.
A CERF exam indicates only the present state of a dog's eyes. Since retinopathy/PRA onsets later in life, a CERF exam cannot predict whether or not a dog will develop the problem in the future. Further, a CERF exam cannot evaluate whether or not the dog will produce it.
Basenjis used for breeding should be tested throughout their life, including after they are retired for breeding, so their retinopathy status is known. Dogs diagnosed with retinopathy should not be bred. Dogs with a parent or offspring with retinopathy should not be bred to each other.
If your dog is diagnosed with PRA, blood samples of your dog, his or her parents, any offspring, and any full siblings should be sent to Dr. Gary Johnson at the University of Missouri. Please contact BCOA for instructions to send samples.

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Umbilical and Inguinal Hernias

 

Umbilical hernias are very common in Basenjis, with most being minor hernias that do not normally cause problems for the dog.

 

For the owner
Umbilical hernias can be repaired at any time; the surgery is often done when a pet is spayed or neutered or during any other procedure requiring anesthesia. Small closed hernias generally do not cause problems; large or open hernias can cause problems if a loop of intestine gets caught in the hernia. Some breeders routinely repair even small closed hernias. Dogs which have had umbilical hernias repaired are still eligible for participation in AKC conformation events.
Inguinal hernias are uncommon in Basenjis. They generally do require surgical repair. Dogs with repaired inguinal hernias are not eligible for participation in AKC conformation events.

 

For breeders
Small closed umbilical hernias generally are not an issue in breeding, although selection away from umbilical hernias is desirable. Large or open hernias should be considered as a strike against breeding stock.
Inguinal hernias are a serious defect, and dogs with inguinal hernias should not be bred.

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