Max
 is unaffected  of
PHPV - Persistent Hyperplastic Primary Vitreous

Persistent Hyperplastic Primary Vitreous is due to the retention of elements of the foetal vascular supply to the lens, the tunica vasculosis lentis. The lesions seen are variable amounts of fibrovascular plaque on the posterior lens capsule and possible posterior cortical cataract. The effect on sight can range from nothing to blindness. Removal of the diseased lens can be complicated by any vascular involvement. Persistent pupillary membrane is of the same origin, but this time remnant strands of the anterior part of the tunica vasculosis lentis remain attached to the iris and may occasionally interfere with sight as the result of associated lens or corneal opacities. Again, any effect on sight is variable, but cataract extraction is possible, whereas corneal opacity is not treatable.
Dr Keith Barnett - HC/PHPV in the SBT (extracts of notes from Staffordshire Bull Terrier Breed Council Meeting, 28th April, 2001

Persistent Hyperplastic Primary Vitreous (PHPV): Dr Barnett said that whilst a few cases of PHPV could be found in a number of dogs, inherited PHPV is found in only a few breeds, e.g. Doberman (particularly in the Netherlands where the breed was quite severely affected with PHPV) as well as Staffords. Unlike HC, which is not congenital (i.e. not present until around 3-4 weeks of age), PHPV is congenital (i.e. is present at birth). PHPV can be identified from as early as 2-3 weeks, although a more accurate diagnosis would be obtained at around 6-8 weeks of age. Although present at birth, PHPV is not progressive except in a few isolated cases, however it is very variable in its degree of severity and can affect both eyes. Dogs suffering from mild forms of PHPV can produce offspring that are severely affected.

During questioning, Dr Barnett confirmed that both PHPV and HC could be diagnosed by the age of 12-18 months. He saw no requirement, therefore, to continue testing purely for PHPV/HC after that age if previous results had been clear. However, he did emphasise that eye tests are designed to look for all eye abnormalities that may be inherited, so it is beneficial to continue testing beyond 12-18 months to regularly check for these. He recommended testing up to any age, but particularly through the breeding cycle of the dog/bitch.

 

Max 
is Clear: of Hereditary Cataract 
             has 2 copies of the normal gene and will neither develop Hereditary Cataract,
                         nor pass a copy of the  Hereditary Cataract gene to any of  her offspring.

 Hereditary Cataract in Staffordshire Bull Terriers

has been recognised as an inherited condition since the late 1970’s. Affected dogs develop cataracts in both eyes at an early age. The condition is not congenital, so the lenses are normal at birth but cataracts appear at a few weeks to months in age, progressing to total cataract (and resulting blindness) by 2 to 3 years of age.

The mutation, or change to the structure of the gene, probably occurred spontaneously in a single dog but once in the population has been inherited from generation to generation like any other gene. The disorder shows an autosomal recessive mode of inheritance: two copies of the defective gene (one inherited from each parent) have to be present for a dog to be affected by the disease. Individuals with one copy of the defective gene and one copy of the normal gene - called carriers - show no symptoms but can pass the defective gene onto their offspring. When two apparently healthy carriers are crossed, 25% (on average) of the offspring will be affected by the disease, 25% will be clear and the remaining 50% will themselves be carriers

The mutation responsible for the disease has recently been identified at the Animal Health Trust. Using the information from this research, we have developed a DNA test for the disease. This test not only diagnoses dogs affected with the disease but can also detect those dogs which are carriers, displaying no symptoms of the disease but able to produce affected pups. Under most circumstances, there will be a much greater number of carriers than affected animals in a population. It is important to eliminate such carriers from a breeding population since they represent a hidden reservoir of the disease that can produce affected dogs at any time.
Breeders will be sent results identifying their dog as belonging to one of three categories:

Max 
is Clear: L-2-HGA (L-2-hydroxyglutaric aciduria)
has 2 copies of the normal gene and will neither develop L-2-HGA, nor pass a copy of the L-2-HGA gene to any of its offspring.


L-2-HGA (L-2-hydroxyglutaric aciduria)

 in Staffordshire Bull Terriers

L-2-HGA (L-2-hydroxyglutaric aciduria) in Staffordshire Bull Terriers is a neurometabolic disorder characterised by elevated levels of L-2-hydroxyglutaric acid in urine, plasma and cerebrospinal fluid.

L-2-HGA affects the central nervous system, with clinical signs usually apparent between 6 months and one year (although they can appear later). Symptoms include epileptic seizures, "wobbly" gait, tremors, muscle stiffness as a result of exercise or excitement and altered behaviour.

The mutation, or change to the structure of the gene, probably occurred spontaneously in a single dog but once in the population has been inherited from generation to generation like any other gene. The disorder shows an autosomal recessive mode of inheritance: two copies of the defective gene (one inherited from each parent) have to be present for a dog to be affected by the disease. Individuals with one copy of the defective gene and one copy of the normal gene - called carriers - show no symptoms but can pass the defective gene onto their offspring. When two apparently healthy carriers are crossed, 25% (on average) of the offspring will be affected by the disease, 25% will be clear and the remaining 50% will themselves be carriers

The mutation responsible for the disease has recently been identified at the Animal Health Trust. Using the information from this research, we have developed a DNA test for the disease. This test not only diagnoses dogs affected with this disease but can also detect those dogs which are carriers, displaying no symptoms of the disease but able to produce affected pups. Carriers could not be detected by the tests previously available, which involved either a blood or urine test detecting elevated levels of L-2-hydroxyglutarate or magnetic resonance imaging. Under most circumstances, there will be a much greater number of carriers than affected animals in a population. It is important to eliminate such carriers from a breeding population since they represent a hidden reservoir of the disease that can produce affected dogs at any time.

Breeders will be sent results identifying their dog as belonging to one of three categories:

CLEAR: the dog has 2 copies of the normal gene and will neither develop L-2-HGA, nor pass a copy of the L-2-HGA gene to any of its offspring.

CARRIER: the dog has one copy of the normal gene and one copy of the mutant gene that causes L-2-HGA. It will not develop L-2-HGA but will pass on the L-2-HGA gene to 50% (on average) of its offspring.

AFFECTED: the dog has two copies of the L-2-HGA mutation and is affected with L-2-HGA. It will develop L-2-HGA at some stage during its lifetime, assuming it lives to an appropriate age.

Carriers can still be bred to clear dogs. On average, 50% of such a litter will be clear and 50% carriers; there can be no affecteds produced from such a mating. Pups which will be used for breeding can themselves be DNA tested to determine whether they are clear or carrier.