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What
is PHTVL/PHPV?
PHTVL/PHPV is a hereditary eye disease affecting the lens
of the eye. To the affected dog, this is a serious condition that
may entail complications demanding veterinary care, and regular eye
tests during the whole life of the dog.
Early in the foetal stage, there is a system of blood vessels
coating the lens. These blood vessels normally regress before the
puppy is born. But in a dog with PHTVL/PHPV this has not occurred
the way it is supposed to, and also the vitreous body of the eye,
has not developed normally. In its mildest form PHTVL/PHPV causes
small pigmented dots in the posterior lens capsule. In more severe
cases the dog has got fully developed blood vessels in the rear face
of the lens and maybe a deformed lens. Then there is a high risk of
cataracts (clouding of the lens) even young puppies can go blind.
What
does it mean to the affected dog?
PHTVL/PHPV is sometimes graded on a
scale from 1 to 6. The mildest form does not affect the eyesight. In
grade 2 to 5 there is increasingly poor vision, and grade 6, the
most severe form, means total cataract, i.e. the eye is completely
blind.
Another complication that might occur is a haemorrhage inside the
eye. This is rather difficult for the dogs’ owner to discover, but
when it happens it is necessary with immediate treatment that is
continued over a long period of time.
How
is it diagnosed?
PHTVL/PHPV is not visible to the naked
eye, but can be seen from the age of 8 weeks in an ophthalmic
examination carried out by an ophthalmologist. The examination is
completely painless. This disease is congenital and will not appear
later in life. However, the gene carrying the disease can exist in a
dog that has been tested clear.
Is
it common in King Charles Spaniels?
In Sweden there are now 14 officially
recognised cases of PHTVL/PHPV, and 1 born in Norway and 1 Finnish bred exported to
Norway.
For pedigrees of these
affected dogs – please
click here »
In
1998-99 the Swedish Kennelclub Veterinarian did a questionnaire
regarding eye anomalies in King Charles Spaniels. This was completed
by the Swedish ophthalmologists. The result of the questionnaire
showed that from a total of 116 examined King Charles Spaniels, 23
showed symptoms that may be related to PHTVL/PHPV. By this time 4
had been diagnosed as having PHTVL/PHPV. Out of the 23 dogs with
symptoms, 3 were born in the 1970’s, 6 in the 1980’s and 13 in
the 1990’s.
Is
it hereditary?
Yes! A dog diagnosed with PHTVL/PHPV
or one that is a known carrier of the disease should not be bred
from. Litter brothers and sisters should not be bred from either. A
dog that has been tested clear can however, still carry the gene and
through it to his or her offspring.
PHTVL/PHPV is a hereditary disease that mainly has been studied in
Dobermans and Staffordshire Bull terriers. Frans Stades in the
Netherlands has investigated the inheritance in Dobermans. He
believes that the inheritance is by a dominant gene, but other genes
are also involved determining the expression of the disease (i.e.
individuals can be affected to varying degrees) and thereby the
symptoms.
What
the Swedish Kennel Club and the breed club have done
The breed club (King Charles
Alliansen) published in its newsletter ”Charlieposten” no 1-2
1994, an article on the first known case in Sweden, Ramblers Annie.
Since 1996 Charlieposten have published the eye examination results
of totally 86 dogs – both clear tests and dogs with diagnosed eye
disease.
At the Annual General Meeting of King Charles Alliansen the members
voted for the introduction of a set of breeding recommendations. The
vote was unanimous. Regarding eyes these recommendations say that
all puppies should be examined by an ophthalmologist before they are
delivered to their new homes. Also all breeding stock must be
examined by an ophthalmologist and be free of hereditary eye
diseases. The examination result must be no older than one year at
the time of mating. The reason for the examinations of adult
breeding stock is to check for other hereditary diseases such as
cataracts and RD, which sometimes appear in the breed. A dog with a
hereditary eye disease shall of course not be bred from.
The KCA (King Charles Alliansen) puppy register should only
recommend litters, where both the sire and the dam have tested clear
as stated in the breeding recommendations.
In August 2000 the Swedish Kennel Club decided to centrally register
all eye examination results in King Charles Spaniels after the KCA
had applied for this. The reason for this was the occurrence of
PHTVL/PHPV in the breed.
What
is the situation like today?
Five years have passed since the breed club introduced
the breeding recommendations. Since then 33 litters have been
registered. Out of
these litters 12 live up to the recommendations.
See all
litters here »
Breeders
have continued breeding from dogs that have produced offspring with
PHTVL/PHPV. Full- and half brothers and sisters of affected dogs
have been bred from. As recent as in 2003 two littersisters of a dog
with PHTVL/PHPV had had a litter each.
In
France there is a Swedish export that is a daughter of Ch Ramblers
Anchor, affected by PHTVL/PHPV. This bitch in France has produced 20(!)
puppies, which in their turn have produced 26 puppies, and many of
those are also being bred from.
What
should the breeders do?
As an absolute minimum the breeders
should at least follow the breeding recommendations! But breeding
King Charles Spaniels is not just about eyes. A good background
regarding heart condition is of prime importance, as the hereditary
heartdisease MVD is the most common hereditary disease in the breed.
Read MVD in King
Charles Spaniels
»
It should be in every breeders own interest to be aware of
where the dangerous defects are and to try and avoid them as much as
possible in their breeding program.
Is
it too much of a risk to buy a King Charles Spaniel?
No, definitely no, but one should be
very careful with exactly what puppy to buy. Luckily enough to the
prospective buyer, PHTVL/PHPV is a disease that can be diagnosed
already when the puppy is about 8 weeks. Therefore noone has to buy
an affected dog without knowing it. This is on the condition that
the breeder follows the breeding recommendation to have every puppy
examined by an ophthalmologist before it is delivered to its new
home. As a buyer you should always demand that your puppy is
examined before you pick it up. You should also demand a copy of the
parents’ heartcertificates and eyecertificates! And I hope that
nobody pays 10.000 SEK or more for a puppy unless the litter is bred in
accordance to the breeding recommendations!
A
good advise to anyone planning to buy a puppy (indifferent what
breed) is to find out as much as possible about the ancestors of the
prospective puppy. The most important thing is after all to get a
healthy dog..
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