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Understanding Fanconi Inheritance

Through Breeding

As a breeder, we are here to create healthy, happy puppies. This was created so that when Breeding, we can avoid Fanconi Affliction.

It is not complicated rocket science, it’s simple genetics and here it is explained in simplex form.

Fanconi is a disease known as a “simple recessive” gene. With these, every dog receives one gene from each parent. The following “Punnett Squares” show what could be produced with every possible breeding due to the genetic makeup of its parents.

You can learn more about the Fanconi Linkage test and FAQs on the basenjihealth.org site.

For all basic purposes, we will use the following notations/abbreviations: N=Normal, or “unaffected” with the gene. N=abnormal or “affected” with the gene

N – CLEAR( Normal Parent not affected with the mutant Fanconi gene)

Nn-CARRIER ( A Parent which carries the Gene)

nn- AFFECTED (a parent which is affected with the abnormal/mutant gene.

The percentages seen below indicate the likelihood or chance that EACH puppy in that litter will have at being Clear, Carrier, or Affected with Fanconi Syndrome.

Some people will tell you that those percentages mean that is how many from each litter will be clear, carrier, or affected. THAT IS WRONG!! Genetics of a simple recessive is based on probability or chance.


How Punnett Squares work:

Each dog has 2 letters in which explain which gene they carry [as described above by example, NN is our example for normal] but technically speaking, a capital letter is used for a good or dominant trait. A lowercase letter is used for a bad or a recessive trait (recessive is not always bad. Tri colored is recessive in Basenjis) and then 1 upper letter and 1 lowercase letter is usually used to explain carriers of a trait but are not affected themselves by the trait they carry. So a blind carrying dog is not blind itself although it can pass it down to its children if bred to the wrong mate)

One of each “letter” (these are the genes) from each parent goes into each “square.” Shown above.

The four squares represent the probability, or chance, that the offspring has of getting the desired (or non-desired) trait.

For each square, the chance or probability is equal to 25%. So you add each one by how many times it appears.

So the AA appears one time. Meaning there is only 25% chance that the offpring will be That gene. The Aa appears twice, which means the offspring have 50% chance of having that gene. And the aa appears once so the offspring have a 25% chance of having that gene as well.

How Punnett Squares Work

 
 A
|
V
 A
|
V
A  --->
AA
 AA
 a ---->
 Aa
 Aa

1. Each dog has 2 letters in which make up a particular gene which they carry [as described above by example, NN is our example for normal] 

2. One of each of these“letters” (these are the genes) from each parent goes into each “square.” Shown above. (arrows show how to read it)

The four squares represent the probability, or chance, that the offspring has of getting the desired (or non-desired) trait.

For each square, the chance or probability is equal to 25%. So you add each one by how many times it appears.

So the "AA" appears one time. Meaning there is only 25% chance of that offpring having that gene. The "Aa" appears twice, which means the offspring have 50% chance of having that gene. And the "aa" appears once so the offspring have a 25% chance of having that gene as well.


Technically speaking:

A capital letter is used for a good or dominant trait (Tho dominant is not always good.) 

A lowercase letter is used for a bad or a recessive trait (**tho recessive is not always bad) 

and An upper and  lowercase letter is usually used to explain carriers of a trait they are not affected by. (*** A carrier example)


  * Ex: Dominant bad chests because of to many strong bad chested breedings and is undesirable.

 ** Ex: Tri colored is recessive in Basenjis but this is not a bad trait

*** Ex: A dog carries the blind gene but never becomes blind itself, (Carrier)

So now that you understand punnet squares, 
Lets get into our chances/probabilities using our original Letters. 
NN = CLEAR, Normal         
Nn = CARRIER, Carries 1 Mutant Gene
nn = AFFECTED, Has both mutant genes and the disease

SAFE BREEDING PAIRS
Acceptable breedings

The following breeding combinations are the ONLY breedings that are recommended by the BCOA Health Committee. 


If a breeder tells you otherwise, go somewhere else for a puppy.


There is absolutely NO BREEDING-- that gives you even the smallest chance of producing Fanconi affected puppies-- that would be worth doing the breeding and taking the risk. 

FANCONI CLEAR to a FANCONI CLEAR

 
N
 N
N
 NN
 NN
 N
 NN
 NN

FANCONI CLEAR to a FANCONI CARRIER

 
 N
 n
N
 NN
 Nn
 N
 NN
 Nn

EACH PUPPY from this litter 

has a 100% Chance of being Fanconi CLEAR, or normal.

because all puppies show NN (which is normal) for the gene.

THIS IS AN ACCEPTABLE BREEDING

EACH PUPPY from this litter 

has a 50% Chance of being Fanconi CLEAR, or normal.
has a 50% chance of being Fanconi CARRIER,(able to pass to children)

THIS IS AN ACCEPTABLE BREEDING

FANCONI CLEAR to a FANCONI AFFECTED

 
n
 n
N
 Nn
 Nn
 n
 Nn
 Nn

EACH PUPPY from this litter 

has a 100% chance of being Fanconi CARRIER, (Able to pass to kids)

                             THIS IS AN ACCEPTABLE BREEDING

WHY CHANCE THE LIFE OF A SWEET PUPPY??

UNSAFE BREEDING PAIRS
DO NOT BREED THESE

FANCONI CARRIER to FANCONI CARRIER

 
 N
 n
N
 NN
 Nn
 n
 Nn
 nn

FANCONI CARRIER to FANCONI AFFECTED

 
 n
 n
N
 Nn
 Nn
 n
 nn
 nn

EACH PUPPY from this litter 

has a 25% Chance of being Fanconi CLEAR, or normal.
has a 50% chance of being Fanconi CARRIER, (Able to pass to kids)
has a 25% chance of being Fanconi AFFECTED, (Has the disease)

THIS IS NOT A GOOD BREEDING

EACH PUPPY from this litter 

has a 50% chance of being Fanconi CARRIER, (Able to pass to kids) 
has a 25% chance of being Fanconi AFFECTED, (Has the disease)

                              THIS IS NOT A GOOD BREEDING  

FANCONI CARRIER to NON TESTED

 
 ?
 ?
 N
 N?
 N?
 n
 n?
 n?

EACH PUPPY from this litter

has a 25% Chance of being Fanconi CLEAR or CARRIER.

has a 25% chance of being Fanconi AFFECTED, (has the disease). The rest of the probability is unknown.

                           THIS IS NOT A GOOD BREEDING

UNTESTED FANCONI to UNTESTED FANCONI

 
 ?
 ?
?
 ??
 ??
 ?
 ??
 ??

Each puppy from this litter 

has the chance of receiving anything...The genetic makeup is completely unknown. Fanconi syndrome could affect All, any, or none of the puppies.

THIS IS NOT A GOOD BREEDING…

Better to play Russian Roulette in Las Vegas!!

Fanconi Carriers

A Fanconi Carrier Basenji makes just as good of a companion as a Clear Basenji does, so do not be misled that you cannot have them as a pet. They are not themselves suffering from the disease and are not affected by the gene that causes the mutation, they simply carry/possess the gene.


Knowing the results of a Fanconi Carrier Basenji is mostly important when they are being used in breeding programs and being purchased as show potential. This is because they carry the gene that causes the affliction, which means it can be passed down to offspring. Proper health testing is important for a Fanconi Carrier breeder because if bred to the wrong partner, some or all of the PUPPIES can become affected with Fanconi syndrome. A FANCONI CARRIER BASENJI SHOULD NEVER BE BRED TO ANYTHING OTHER THAN A FANCONI CLEAR DOG.


But having a carrier as a pet does not harm anyone or anything because pets are spayed or neutered and there is no chance/fear of passing the mutation down to their puppies.

What matters is that the puppy is FREE from Fanconi Syndrome and that they are not Afflicted/Affected with Fanconi during their lifetime.


There is absolutely no reason to buy a puppy from a breeder that is not following the recommended breeding practices set forth by the BCOA (Basenji Club of America) Health Committee.


Breeding against these practices is not only irresponsible but it is NOT fair to the resulting puppies and their new owners!

PLEASE ask about other diseases that can affect your Basenji. PRA and HIP DISPLAsIA are not simple recessive diseases therefore they do not follow the above probabilities. BUT there is absolutely no reason to breed a Basenji that is AFFECTED with PRA or HIP DISPLASIA.


Anyone telling you otherwise is irresponsible in their breeding practices.


For info on Fanconi and how Amore Basenji’s Strives to produce only puppies that will NEVER become afflicted with this disease, please contact Whitney at [email protected] or email [email protected].

BCOA Explains Fanconi:

Fanconi Synrdome:

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 marker test, which looks at multiple markers, was used from 2007 to August 2011.  Dogs tested using this test have OFA results which are listed as "probable" results.  The current direct DNA test, introduced in August of 2011 and available through OFA, gives definitive results.  For more information about this test click Direct Fanconi Syndrome DNA Test FAQ.


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.


Owners should periodically "strip test" their dogs for glucose in the urine, starting at age 3. Presence of glucose in the urine suggests the need for further testing to determine if the dog has Fanconi. This is especially important if the dog does not have a tested probable clear parent. In that case, monthly testing is generally suggested.


Urine glucose test strips (not blood test strips), such as those used by diabetics, are inexpensive and can be purchased at most pharmacies. The strip should be placed in the Basenji's urine stream and then read as specified in the strip instructions. If it is not possible to place the strip in the urine stream, then the owner may need to catch the urine. Some owners use a pie pan, ladle, or serving spoon.


A positive result (glucose present) suggests the possibility of Fanconi, but is not sufficient for definitive diagnosis. Owners should then go to their vet for 

further testing, which would normally include a blood glucose level.


Strip testing indicates only the current presence or absence of glucose in the urine. It does not diagnose Fanconi and it is valid only on that day. A dog that test strips normal now may later develop Fanconi.


Because elevated urine glucose is also found in diabetes, Basenjis with Fanconi are often misdiagnosed with diabetes. Diabetes will show high blood glucose along with urine glucose. In Basenjis, a combination of urine glucose and normal or low blood glucose strongly suggests Fanconi syndrome. Venous blood gas studies can verify an electrolyte imbalance consistent with Fanconi syndrome. A veterinarian should evaluate dogs that have Fanconi symptoms but are not spilling sugar.


Pets can be DNA tested to verify a Fanconi diagnosis or to help assess their likelihood of coming down with Fanconi. However, even if your dog is DNA tested clear or carrier, you should still strip-test, as there is a small risk of error with the linkage DNA test and a small number of false positives and false negatives have occurred.


Work is continuing on a direct DNA test for Fanconi syndrome, which will test for the actual mutation. This will increase test accuracy.


More detail is given on the page for Fanconi Test FAQ.


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 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.

More detail is given on the page for Fanconi Test FAQ.


Additional Information

Current OFA statistics are available online at OFA website — just highlight Basenji and click Search. Percent normal are dogs that are neither carriers nor affected. Percent abnormal is the same as percent affected.


For DNA tests, if you take 100, subtract the % percent normal, and subtract the percent affected, you will get the percent that are carriers, equivocal, or indeterminate.


Note that all percentages are cumulative. For Fanconi, the percentage affected of newly tested dogs is lower than the cumulative average, because the higher original incidence is averaged with the lower new incidence.


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.


The Fanconi Protocol can be downloaded HERE.



As described by Khani's Basenjis. http://khanisbasenjis.com/fanconi.html  Slightly revised to help me better understand and hopefully you too