The Truth About PLL/ And Other Testing

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The Truth About PLL/ And Other Testing

What is
Primary Lens Luxation?
PLL

 

 

Primary Lens Luxation is an eye problem well known
i
n many Terrier breeds as well as Tibetan Terriers, Chinese Cresteds ,
Australian Cattle Dogs, and other breeds.

The lens is held in place in the eye by fibers known as zonules.
If these zonules stretch or break, the lens can fall out of place, or luxate.
When this happens it often requires immediate veterinary attention to remove
the displaced lens and prevent painful secondary glaucoma, and sometimes loss of vision.

How to avoid PLL !!


Research at the University of Missouri led to identification of a DNA mutation that predicts which dogs are at risk for developing lens luxation as they age.
Working independently and using other breeds, the researchers at the Animal Health Trust found the same mutation a few months later.
This independent confirmation of the finding makes both labs confident that the correct mutation has been identified,
and that the test is valid for many breeds.
A simple DNA test will reveal if a dog is
NORMAL (has 2 normal copies of the gene),
a CARRIER (has one normal copy and one mutated copy of the gene),
or AFFECTED (has 2 mutated copies of the gene).
Wise use of this test will allow breeders to avoid producing individuals destined to develop lens luxation,
while still retaining many other desirable traits in their dogs.

 

Testing and Inheritance of PLL From pedigree studies done previously, there has been general agreement that
PLL is inherited as a simple recessive trait. This means that a dog needs 2 mutated, or “bad” copies of the gene to show the disease.
With the PLL mutation identified, and the research groups able to compare notes on the dogs used in the study,
it has become apparent that there are some exceptions.
While the vast majority of dogs with PLL have tested AFFECTED,
as small percentage of the dogs that test CARRIER are also at risk of developing PLL.
Owners and breeders should be aware of this and understand the implications of the test results so that they can make well-informed decisions
for the future of individual dogs, and the breed as a whole.

Dogs that test AFFECTED have 2 mutated copies of the gene.
The vast majority of these dogs will luxate at 4-8yrs of age, the typical age of onset for PLL.
There were a few dogs in the study group that tested as AFFECTED but did not luxate until after 8 yrs of age,
and some dogs testing AFFECTED have died from other causes without luxating.
A search of published veterinary literature revealed that about 10% of the dogs
reported to be clinically affected with PLL had onset of symptoms after 8 yrs of age.
Because of this, the test results will say “AFFECTED/HIGH RISK”. 

 

 

 

As stated earlier, dogs testing CARRIER are at a slight risk of developing PLL.
Carriers have one normal and one mutated copy of the gene.
They could pass either the normal copy or the mutated copy on to their offspring.
Because there were a very few cases of dogs in the research groups testing CARRIER who did appear to have PLL,
the test results will say “CARRIER/LOW RISK”.

A dog testing NORMAL has 2 normal copies of the gene,
is not at risk for developing PLL, and can only pass a normal copy of the gene to any offspring.

 

Breeders and individual owners are now able to test any dog using the testing
kit that can be ordered online through the
OFA website (www.OFFA.org)

.
DNA is collected using a cheek swab, and the bar-coded sample will be tested by the Animal Molecular Genetics Lab
at the University of Missouri, with results reported directly to the owner by OFA.

Above reference found here

http://www.caninegeneticdiseases.net/GLX/PLLancmt.htm

Do not beleive everything you read on breeders websites ,
breeding carriers of this gene WILL PRODUCE dogs with future medical issues.
As one breeder whom chooses to breed carriers of this gene states,

 

 

 Why it is ok to breed them, note , this breeder does breed and sell affected,
carrier puppies to YOU, the un-knowing public, and justifies their actions.
YOU PAY FOR THIS HEARTACHE.

   The following is one breeders opinion,

not the opinion of 5280 Toy Rat Terriers

 

 

Breeding Advice from another a Breeder of  Rat Terriers

“Our research has also demonstrated that the frequency of the PLL mutation is extremely high in the PLL-affected breeds that we have studied in depth.
This means that allowing only CLEAR dogs to breed could have a devastating effect on breed diversity and substantially
increase the likelihood of new inherited diseases emerging.
Therefore, we strongly advise breeders to consider all their dogs for breeding, regardless of their PLL genotype.
GENETICALLY AFFECTED and CARRIER dogs can be bred with,
but should only be bred to DNA tested, CLEAR dogs.
All puppies from any litter that has at least one CARRIER parent should be DNA tested,
so that the CARRIERS can be identified and followed clinically throughout their lives.
This practise should be followed for at least one or two generations,
to allow the PLL mutation to be slowly eliminated from the population without severely
reducing the genetic diversity of breeds at risk.”
 

  5280 Toy Rat Terriers Response
Really,  ok so the plan should be to breed genetically unsound dogs, that will in the long run,
cause you alot of heartache for medical reasons.
HUMMMM…..
We should all rush out and buy one of their carrier puppies,

that will mutate, at say 8 years of age.
Tell me, you want one of those puppies, or more of those lies……. NOT ME…..
WE BREED FOR LIFE LONG COMPANIONS.
Interview your breeder well, know their lineage….

Another point, the gene pool of the rat terrier is so vast,
there is no reason to breed carriers of this painful,

costly, damaging gene.  Where is the sanity in this?

 

 

 

Note: CARRIER PUPPIES WILL CARRY THIS MUTATED GENE

As stated earlier, dogs testing CARRIER are at a slight risk of developing PLL.
Carriers have one normal and one mutated copy of the gene.
They could pass either the normal copy or the mutated copy on to their offspring.
Because there were a very few cases of dogs in the research groups testing CARRIER who did appear to have PLL,
the test results will say “CARRIER/LOW RISK”.
The article did state a small % are at risk of Luxating, I am not willing to take that risk with my family pet , are you?

WHICH COPY DID YOUR PUPPY GET ,
DID YOUR BREEDER TELL YOU, OR TEST YOUR BELOVED PUPPY PRIOR TO PURCHASE?
CARRIER PUPPIES ARE RISKY INVESTMENTS.

http://www.caninegeneticdiseases.net/GLX/PLLancmt.htm

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