FOUNDED 1973

HEALTH ISSUES

In general, the Staffordshire Bull Terrier is a healthy, robust breed.  There are, however, a couple of hereditary health issues which need to be considered when you are buying a new puppy or if you are planning to breed from your dog/bitch

 FOR MORE DETAILED EXPLANATIONS ABOUT THESE CONDITIONS AND THE GENETIC TESTING

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NEUROLOGICAL CONDITION– L-2-HGA (L-2 hydroxyglutaric aciduria)

In the past few years a small number of Staffords have been diagnosed with a metabolic disorder; its clinical title is L-2 hydroxyglutaric aciduria or L-2 HGA. This condition has manifested itself in varied ways with dogs exhibiting behaviour changes and dementia (staring at walls, getting stuck under tables and in corners, loss of obedience and house training), anxiety states, having full blown seizures, as well as exercise intolerance, ataxia (unsteady gait), tremors and muscular stiffness. Dogs from differing bloodlines have been found to be sufferers and the number of affected dogs diagnosed has risen. The disorder (and a similar linked disorder, D-2 HGA) is found in humans, again very rare, but nevertheless, devastating for the families affected by it. The disorder has an autosomal recessive method of inheritance, meaning that both parents must be carriers of the defective gene to produce affected offspring.

Research into the disorder as it affects canines was undertaken at the Animal Health Trust in Newmarket, as well as at universities in Holland and USA. Magnetic Resonance Imaging (MRI) shows changes in the grey matter of the brain in all the dogs.

There is NOW a genetic screening test to determine which dogs are carriers of the gene that causes L2.  ALL BREEDING STOCK must be screened in order to eradicate this condition in the future.

TESTING CAN TAKE UP TO 6 WEEKS FOR RESULTS TO COME BACK SO MAKE SURE YOU HAVE SUBMITTED BLOOD SAMPLES LONG BEFORE YOU PLAN YOUR MATING

HEREDITARY CATARACTS - HC

It is known that HC is inherited by and autosomal recessive path (i.e. both parents must be carriers of the defective gene to produce and affected offspring). HC is a progressive condition and this means that although a puppy is not born with cataracts they will start to develop at a juvenile age. (maybe from 8 months onwards), and will progress until the dog is totally blind. This condition is bilateral which means is affects both eyes equally. Thanks to the tireless research by the Animal Health Trust in Newmarket there is a now a DNA Test for Hereditary Cataracts.

Information about DNA testing for L-2-HGA and HC and downloadable forms can be found on the Animal Health Trust website

PERSITENT HYPERPLASTIC PRIMARY VITREOUS – PHPV

The mode of inheritance of PHPV is not so clear, but it is known that it is a congenital condition (present at birth) and that it is not progressive. This means that if a puppy is born with PHPV it can be detected by ophthalmic screening from 6 weeks of age and if it is affected, whatever the condition of the problem at that stage it will not change throughout the dogs life.

Either of the above conditions can be operated on, but it is a serious operation and can be traumatic and very expensive. It is not always covered by insurance due to the hereditary nature.

Even though the genetic test is now available for Hereditary Cataracts it is still important to screen for PHPV. It is recommended that litters are screened – the result will enable puppy buyers the knowledge that their puppy is unaffected by PHPV and in the worst event that an affected puppy is detected the breeder can arrange for the entire litter to submit DNA samples to further the research in to PHPV.

POSTERIOR POLAR SUBCAPSULAR CATARACT - PPSC

This type of cataract is found in other breeds, particularly the Labrador and Golden Retriever.
It usually remains as a small, punctuate cataract and doesn’t usually lead to sight problems in these two breeds. It has been placed on schedule 3 of the BVA/KC/ISDS Eye Scheme because a number of Staffords that have been through the Scheme have been found to have this type of cataract. This type of cataract cannot be detected through litter screening. The mode of inheritance is unknown and it has a variable age of onset.

IT IS RECOMMENDED THAT BREEDING STOCK SHOULD BE TESTED PRIOR TO MATING TO DETERMINE THAT THE DOG IS CERTIFIED UNAFFECTED AT THE TIME OF MATING Eye Testing Clinics

Understanding Recessive Genes

Recessive genes are responsible for many aspects in dogs, such as the production of blue or liver coats, and most do not affect the dog’s physical well-being. A few however do cause health problems. Two have been described in Staffords – hereditary cataract (HC), causing blindness in young dogs, and L-2-Hydroxyglutaric Aciduria (L-2-HGA), a metabolic condition that affects the brain, causing seizures that may be misdiagnosed as epilepsy.

All dogs have two copies of every one of their thousands of genes with the exception of those on the sex chromosomes in the case of males. One copy of each comes from the sire and the other from the dam. The copies of each gene may not be identical but each will be at the exact same position on the appropriate chromosome. Differences between pairs of genes, mutations, are the result of little biochemical errors occurring somewhere in the replication process between generations.

With recessive genes the ‘original’ variant, let’s call it ‘X’, produces the ‘normal’ effect as long as one copy of ‘X’ is present. If a mutation has occurred at some point, resulting in a recessive variant, ‘x’, then the normal effect will be produced as long as it is paired with ‘X’. ‘X’ is thus considered to be dominant to ‘x’, or putting it another way ‘x’ is recessive to ‘X’. X/X will naturally produce the normal effect but if x/x is produced then the resultant effect may be totally different.

With both HC and L-2-HGA three gene combinations are possible as you will have realised already –

1. X/X – the dog is clinically unaffected and is not a carrier of the condition, as it does not possess ‘x’, and thus cannot pass it to  its off-spring.

2. X/x – the dog is clinically unaffected but is a carrier as it possesses ‘x’ which, on average, it will pass on to half its progeny.

 3. x/x – the dog is affected with the appropriate condition and were it used for breeding it must pass the defective ‘x’ gene to all its progeny.

The aim of any control measures must be simply to prevent any clinically affected animals being born and eventually to eliminate the defective ‘x’ from the breeding population. With the development of laboratory tests for the recessive genes that cause the two conditions (tests for L-2-HGA are already available) the first step must be not to breed two carriers together – ensuring both sire and dam are tested prior to mating should guarantee this. Previously the only way of knowing a dog is a carrier is when it has produced affected off-spring. With careful selection, breeders, who have lines affected with either condition should be able to get rid of the defective genes within two or three generations while hopefully maintaining the quality of stock they desire.

Clearly not using any carriers at all in breeding programmes would soon eliminate the recessive genes for HC and L-2-HGA and some may advocate this. However, this would cause a possibly serious reduction in the gene pool, even in a breed like the Stafford that has a comparatively large pool, and could inadvertently permit the emergence of other genetic defects.

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