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
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
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.
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
Any planned Basenji litter should have at least one
parent that tests probable clear, to minimize the chance
of producing affected puppies.
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.
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.
Hypothyroidism is easily treated with an inexpensive
thyroid supplement; the dose may need periodic
adjustment, and this should only be done with veterinary
Pet owners may want to have their vet periodically check
their dogs, especially if they show any symptoms that
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
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.
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.
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
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.
Persistent Pupillary Membrane
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.
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
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
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
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.
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
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.
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.
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
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.
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.
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.
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.