The following is a reproduction of the P.A. leaflet that was produced by the Boxer Breed Council. It must be stressed that it is included on this site for HISTORICAL purposes only. P.A. is now no longer considered a problem within the Boxer Breed, due largely to the control scheme implemented and the co-operation of breeders involved at that time.
BOXER BREED COUNCIL OF THE U.K.
PROGRESSIVE AXONOPATHY (PA) OF BOXER DOGS
(An advisory leaflet for all Boxer owners: revised 1989)
PA is a disease affecting the nervous system.
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Although similar diseases are found in other breeds of dogs and other animals, this particular disease is only found in Boxers.
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PA is inherited, the mode of inheritance being that of a simple recessive such as that for white pups.
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Less than 60 cases have been identified since the disease was first recognised. Suspect cases (lacking veterinary diagnosis) have also been found but remain few in number. P A as a disease has therefore never been a major breed problem; the difficulty for the breed has lain with the large number of clinically normal P A carriers.
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A scheme was drawn up by the Breed Council in 1981 to combat and control the spread of P A and was directed at the carrier animals. It received the support of all clubs and their membership throughout the country.
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The control scheme remains in operation and should continue for several years to come.
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For the scheme to function, all suspect cases must be examined by a specialist Vet and notification sent to Breed Council. Therefore, if a vet in general practice suspects a puppy has PA he should refer it to one of the named diagnostic centres for final diagnosis.
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As far as a pet owner is concerned it should be emphasised that (1) the likelihood of any adult Boxer developing P A, whatever its ancestry, is negligible and (2) there is no reason why a possible carrier puppy should not be a perfectly normal, healthy animal so long as the breeder has followed the Breed Council Control Scheme.
HISTORY
Progressive Axonopathy was first described in 1980 by Griffiths, Duncan and Barker (J. Small Anim. Pract (1980) 21, 29-43) as a neurological disease specific to Boxers.
The published paper was brought to the attention of the Breed Council at their 1980 Spring Meeting by Dr Bruce Cattanach, an animal geneticist and Boxer breeder and exhibitor, who started collecting information supplied by the veterinary profession and breeders throughout the country. From this information it was established that P A was an hereditary condition and that the mode of inheritance was that of a simple recessive gene. The initial findings were presented at the Autumn Breed Council meeting when it was decided that details of the disease should be circulated to members of all breed clubs and that assistance of the veterinary profession in general practice be sought through the publication of letters in veterinary journals (J. Luckhurst, Vet Rec (1980) 107, No. 17, 407). An Axonopathy fund was set up by means of a levy paid by the breed clubs.
At Boxer Chatter' 81, held the day after Crufts, Dr Griffiths described the pathology and symptoms of the disease and, with the use of a film, illustrated the dramatic effect it had upon affected Boxers. Dr Cattanach then presented a summary of the genetical findings. A week or two later the names of three well known stud dogs who had proven to be carriers were announced by their owners. They and all other proven carriers contacted have been withdrawn from breeding.
At the Spring '81 Breed Council meeting the subject of PA was again discussed at length. A panel of six people, comprising Sheila Cartwright. Bruce Cattanach, Pat Heath, Bill Law, John Luckhurst and Pat Withers, was setup to deal with the immediate problems under the chairmanship of Group Captain Sutton. The terms of reference were:-
1 To formulate a provisional policy for the control/eradication of PA, this to be submitted to all breed clubs for their approval.
2 To act in an advisory capacity and to disseminate information to breed clubs both in this country and abroad.
3 To produce a pamphlet explaining P A together with lists of proven carriers.
4 To monitor the situation.
5 To establish a referral system for the diagnosis of suspected cases by specialist veterinarians.
6 To investigate the possibility of test matings.
7 To report to the Boxer Breed Council every six months.
In May '81 the panel sent copies of pedigrees of all established cases of P A to the breed clubs together with lists of proven carrier dogs and bitches and the first draft of a scheme recommended for the control/eradication of P A. The outline of this scheme had already been presented by Bruce Cattanach to the KC/BVA Standing Committee for assessment and had met with their approval. The scheme was discussed by club committees and presented to members and Boxer owners generally at open meetings held throughout the country. Subject to minor amendment it was accepted by all clubs and their membership.
In November '81 a further letter was published in a veterinary journal (I. R. Griffiths, Vet Rec. (1981) 100, 458), this providing information for vets on the control scheme and seeking their assistance with its implementation. Early in 1982 the pamphlet was reproduced by the British Small Animals Veterinary Association and distributed in one of their Newsletters.
Following the occurrence of PA in Norway in late 1987 Dr Cattanach reconvened the panel to consider the pedigree implications for British breeding stock. Recognising that the Norwegian cases identified P A carriers in the close ancestry of several top British stud dogs of the previous decade, the panel put forward the proposition to Breed Council that the P A control scheme recommendation 'that no dog that has a proven carrier within five generations be used at stud' be reduced to 'four generations'. The object was to avoid excessive depletion of current young breeding stock. At the March 1988 meeting the proposition was unanimously accepted by all member clubs. However, at the following October 1988 meeting they were able to reverse this decision when the results of retrospective analyses of the breeding records of most of the stud dogs originally implicated showed that they were in fact clear of the disease.
VETERINARY ASPECTS OF PA
The clinical signs and diagnostic features of P A are caused by disorders both in the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves to muscles). The main effect of the disease is upon the nerve axon and its medullary sheath, there being a reduction in the number of myelinated nerve fibres and a lessening in the thickness of the medullary sheath which surrounds the axon. This results in a swelling and ballooning of fibres and their ultimate degeneration.
A Clinical Signs
1 Progressive loss of co-ordination initially affecting the hind limbs. This causes a wobbly, unsteady gait, a wide based stance and a marked tendency for the limbs to cross when turning sharply.
2 Weakness, initially affecting the hind limbs.
3 Possible involvement of forelimbs with intensification of other signs to the point that the dog may tend to fall over and ultimately be unable to walk unaided. Since the disease was first described one or two animals have stabilised for a time, i.e. they have not appeared to worsen any further but neither have they improved.
4 Dogs and bitches are equally affected.
B Diagnosis
This is carried out by specialist vets at certain veterinary centres and is made on the and had met with their approval. The scheme was discussed by club committees and presented to members and Boxer owners generally at open meetings held throughout the country. Subject to minor amendment it was accepted by all clubs and their membership.
In November '81 a further letter was published in a veterinary journal (I. R. Griffiths, Vet Rec. (1981) 100, 458), this providing information for vets on the control scheme and seeking their assistance with its implementation. Early in 1982 the pamphlet was reproduced by the British Small Animals Veterinary Association and distributed in one of their Newsletters.
Following the occurrence of PA in Norway in late 1987 Dr Cattanach reconvened the panel to consider the pedigree implications for British breeding stock. Recognising that the Norwegian cases identified P A carriers in the close ancestry of several top British stud dogs of the previous decade, the panel put forward the proposition to Breed Council that the P A control scheme recommendation 'that no dog that has a proven carrier within five generations be used at stud' be reduced to 'four generations'. The object was to avoid excessive depletion of current young breeding stock. At the March 1988 meeting the proposition was unanimously accepted by all member clubs. However, at the following October 1988 meeting they were able to reverse this decision when the results of retrospective analyses of the breeding records of most of the stud dogs originally implicated showed that they were in fact clear of the disease.
VETERINARY ASPECTS OF PA
The clinical signs and diagnostic features of P A are caused by disorders both in the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves to muscles). The main effect of the disease is upon the nerve axon and its medullary sheath, there being a reduction in the number of myelinated nerve fibres and a lessening in the thickness of the medullary sheath which surrounds the axon. This results in a swelling and ballooning of fibres and their ultimate degeneration.
A Clinical Signs
1 Progressive loss of co-ordination initially affecting the hind limbs. This causes a wobbly, unsteady gait, a wide based stance and a marked tendency for the limbs to cross when turning sharply.
2 Weakness, initially affecting the hind limbs.
3 Possible involvement of forelimbs with intensification of other signs to the point that the dog may tend to fall over and ultimately be unable to walk unaided. Since the disease was first described one or two animals have stabilised for a time, i.e. they have not appeared to worsen any further but neither have they improved.
4 Dogs and bitches are equally affected.
B Diagnosis
This is carried out by specialist vets at certain veterinary centres and is made on the following grounds.
1 The animal is a Boxer.
2 The age - usually three to six months.
3 Loss of paw position sense, loss of reflex movement when balance is disturbed and peculiar hip-swaying gait
4 Loss of patella reflex (kicking action when tapped below the knee).
5 No loss of pedal reflex or pain sensation. Little muscular wasting.
6 A reduction in the nerve conduction velocity and sensory nerve potential. These are electrophysiological tests performed under anaesthesia.
7 Biopsy of the peripheral nervous system. The lesions are suggestive of the condition but do not provi4e complete diagnosis.
8 Autopsy, leading to the examination, both by light and electron microscopy, of prepared sections of the central nervous system for lesions specific to the disease.
Diagnostic Veterinary Centres
Arrangements have been made with the following specialist vets to examine all future possible cases of PA as to ensure a totally reliable diagnosis. Referral should be made through the General practitioner.
Glasgow: Dr. IR. Griffiths, MRCVS, BVMS, PhD. Dept of Veterinary Surgery, University of Glasgow Veterinary School, Bearsden Road, Glasgow, G61 lQH. Tel: 0419422301.
Liverpool: Mr G.C. Skerritt, MRCVS, BVSc. Dept. of Veterinary Anatomy, Faculty of Veterinary Science, University of Liverpool, PO Box 147, Liverpool, L69 3BX. Tel: 051-709 6022.
Bristol: Dr P Wotton, BVSc., P .L.D., MRCVS, Dept of Veterinary Medicine, School of Veterinary Science, University of Bristol, Langford House, Langford, Bristol BS18 7DU. Tel: 0934 852581
Cambridge: Dr A.C. Palmer MA, ScD., MRCVS, Dept of Clinical Veterinary Medicine, University of Cambridge, Madingley Rood, Cambridge CB3 OES. Tel: 0223 337642.
Humberside: Mr J. Barker BVetMed, MRCVS, Eastfield Veterinary Clinic, Station Road, North Thoresby, Grimsby, South Humberside DN36 5QU. Tel: 0472 840209.
Northern Ireland: Dr R.M. McCracken, Veterinary Research Laboratories, Stormont, Belfast BT4 3SD. Tel: Belfast 023-76001
Eire: Dr BJ. Sheahan, Dept of Veterinary Pathology, Faculty of Veterinary - Medicine, Veterinary College Dublin, Ballsbridge, Dublin 4. Tel: Dublin 687988 ext 05.
Consultant Geneticist : Dr H.M. Cattanach, MRC Radiobiology Unit, Chilton, Didcot. Oxon OX II ORD. Tel: 0235 834393 (day); Home 0235835410 (evenings).
INHERITANCE OF PA.
The evidence that PA is inherited is as follows:-
I PA only occurs in Boxers
2 It occurs only within certain family lines and crosses between them.
From the above and from the finding that the frequency of affected puppies within the litters accords with a calculated expectation, it has been determined that PA is inherited as a simple recessive, just like that for the white puppy in the Boxer breed.
The following diagrams show the types of matings that are possible within the breed. No matings which involve affected animals are shown since the onset of P A occurs so early in life and the symptoms are so severe that it is highly unlikely that such animals could be used for breeding.
Three points should be noted:
1 To produce an affected puppy both parents must be carriers.
2 It is the clinically normal carriers which spread the disease throughout the breed.
3 Since carriers are only identified when they produce an affected puppy, the number of carriers is liable to be far greater than the few so far known.
GEOGRAPHICAL LOCATION OF KNOWN CASES
Up until 1987 PA had only been reported in Boxers bred in the UK. The known cases derived from different areas of the country and the only factor shared by them all was common ancestry. Three affected litters were then detected in Norway. These were closely related to each other and traced back through common lines to a bitch exported to Sweden from the UK several years earlier. This bitch shared a close common ancestry with all British PA family groups.
INCIDENCE OF PA
Up until the PA control scheme began to take effect only 36 cases off A had been positively diagnosed at specialist veterinary hospitals and only 9 other possible 'historical' cases, lacking full veterinary diagnosis had been identified. In total, these 45 cases derived from 29 litters. These had been found over a period of about 8 years during which time many thousands of Boxers had been bred in this country. Therefore, although cases may well have been missed, from the onset the incidence off A in the breed could not have been high. The original problem was that a significant proportion of top show dogs had carriers within the first few generations of their pedigrees and many would therefore have been carriers.
Only 2 further litters, these containing 6 affected pups, have since been found in the UK despite extensive screening of the breed both by breeders and vets. More importantly, with the passage of time it is now improbable that any show breeding stock has known carriers within 3 generations and only a relatively small number of show Boxers may have known carriers within 4-5 generations. The likelihood of unknown carriers deriving from more distant generations will also be decreasing. It may therefore be concluded that the incidence of the PA gene amongst present day British show stock must now be very low -BUT CONTINUED MONITORING OF LITTERS FOR PA REMAINS ESSENTIAL. To date, the possible number of possible P A cases recorded in British Boxers is 53, these from 32 liners. The number includes 2 further possible cases from one 'historical' litter.
ORIGIN OF PA IN THE BREED
With the help of the Norwegian pedigree information it has been possible to trace the lines of descent of PA back to, or close to, its beginning. It seems likely that the original mutation occurred in a British-bred Boxer in the 1950's but could have derived from an earlier generation. The original carrier must lie behind Summerdale Knockout and Ch Hazefield barrister through which all PA lines, detected so far, trace. On the basis of the evidence available the most likely source of PA is Ch Wardrobes Miss Sable.
CONTROL OF PA
A Objectives
1 To prevent further cases of P A being produced.
2 To reduce as far as is practicable the number of carriers in the breed.
3 To achieve the above objectives by some means, which does not eliminate whole bloodlines and lose the breed otherwise valuable breeding animals. i.e. to establish a policy which will allow individual breeders to clear their stock.
B Methods available
1 Culling If all known carriers and their decendants were withdrawn from breeding and such action was carried out wherever PA might be subsequently appear then the disease could be eradicated. However, if carried out in full, this action would defeat objective 3 above.
2 Outcrossing If, as has appeared possible, PA was limited to a very few family lines then selective out-crossing to other lines would prevent the production of affected animals. Furthermore, If such selective breeding away from known sources of PA were continued over several generations then the frequency of carriers in the bloodlines concerned would decrease. The risk of descendants of proven carriers would, on average be reduced by one half in each generation.
Generation Risk of being a carrier
1st 50.0% 1 in 2
2nd 25.0% 1 in 4
3rd 12.5% 1 in 8
4th 6.25% 1 in 16
5th 3.13% 1 in 32
However, the main family lines were very large. A policy of continued out-crossing away from PA without any restrictions on the numbers of potential carriers used for breeding would still leave many carriers among their descendants even after five or more generations. Therefore this procedure alone, would not be effective in eliminating PA from affected bloodlines.
3 Test Mating If descendants or proven carriers could be test mated, those non-carriers among them could be distinguished from carriers and be declared clear of PA, despite their ancestry. Three types of test-mating are theoretically possible; two others are of present day application.
(a) Test animal (dog or bitch) x affected animal(s). If one or more litters containing a total of at least 7 progeny were reared and none developed PA, then a test animal could be declared clear. However, because most affected animals become severely physically impaired at an early age, few, if any could ever be used for breeding. This type of testing is therefore not a practical proposition with this disease.
(b) Test animal (dog or bitch) x proven carrier. If one or more litters containing a total of at least 16 progeny (possibly only 10 in the case of bitches) were reared and none developed PA, then the test animal could be declared clear. However, since (i) the number of pups required for test mating bitches is so high and (ii) there are very few proven carrier bitches available for test mating dogs, this type of test is unlikely to have much future application but could be applied retrospectively on the basis of past breeding performance.
(c) Test animal (dogs only) x first generation progeny of proven carriers. If litters containing about 50 progeny were reared from 7 or more bitches and none developed PA, then a dog could effectively be proved clear. However, since (i) the number of progeny required to clear a dog by this procedure is so high and (ii) a high proportion would be carriers and therefore a further burden on the breed this type of test cannot be justified but, as with (b) above could be applied retrospectively on the basis of past breeding performance.
(d) Test animal x ancestor(s) in line to the PA carrier in the pedigree. Should an animal have a single PA carrier in its pedigree, matings back to ancestors in line to the carrier (e.g. dam, grand-dam, etc) serve as test matings. The rationale is that the test animal can only be a carrier if the relevant ancestors are carriers. The number of pups required for clearance purposes is as for (b) above.
(e) Inbreeding on test animal. The rationale is that inbreeding upon any animal that carries PA is liable to produce the disease. The closer the inbreeding the more effective the test Thus, for dogs, litters from about 6 daughters might be adequate for clearance purposes, depending on the litter size. However, other forms of inbreeding e.g. half-brother x half-sister matings on the test animal, can also contribute some information.
It should be noted that information from all kinds of test matings can be combined for clearance purposes, but it is advisable to seek genetical advice before embarking on upon any test-mating programme. All test-matings should be conducted under the Breed Council Control Scheme and the Secretary kept informed.
TEST MATING IS NOT RECOMMENDED FOR ANIMALS THAT ARE AT HIGH RISK OF BEING CARRIERS.
The Control Scheme presented below incorporates the essential elements of all methods that are practical for PA control and, if implemented fully, should ensure that PA remains rare and possibly even become extinct in the show Boxer.
NB. Similar schemes have been implemented in Scandinavian countries.
BOXER BREED COUNCIL SCHEME FOR THE CONTROL OF PA
(1981, with minor amendment 1989)
On the basis of the available evidence on PA in the breed and on the merits of the possible control procedures, the following scheme has been adopted by Breed Council and will be implemented by Breed Clubs; Breed Clubs are responsible for educating their members in the problems and implications of PA.
All proven carriers be withdrawn from breeding — except when used for test-mating under Breed Council controlled conditions.
2 Since all first and second generation offspring of proven carriers (children, grandchildren) and brothers and sisters of proven carriers have an unacceptably high risk of being carriers, it is strongly recommended that they should not be bred from unless:
a. they are proven clear either by test-mating or, in the case of older animals, on the basis of retrospective analysis of their past breeding record.
b. there is no alternative other than to disband a whole bloodline (i.e. stock registered with a breeder’s affix for a minimum of three generations).
In this situation it is recommended. :
i. that Breed Council be notified of the proposed mating and supplied with relevant pedigrees in order that the situation can be monitored.
ii. that only bitches be bred from.
iii. that at most only one or two litters are taken from such animals.
iv. that these bitches be selectively out-crossed away from all know sources of PA.
v. that all pups sold from such litters should be registered and have their registrations endorsed ‘not for breeding’ by the K.C., and, in addition, the name and address of the purchaser of the puppies be sent to Breed Council.
3. In later generations, i.e. 3rd generation onwards, the following procedures are recommended for bitches:
a. selective out-crossing (i.e. avoidance of carriers on both sides of the pedigree) to be continued until there is no proven carrier within at least 5 generations.
b breeders should note the levels of risk that still exist and continue
endorsement of registration of all pups sold for 5 generations.
For dogs :
Since a stud dog can inflict major damage upon the breed should he be a carrier and since the risk of him being detected as a carrier will be small with a policy of out-crossing, it is recommended that no dog who has a proven carrier within 5 generations should be used at stud unless it has been test-mated and proven to be clear of PA.
4. All owners of stud dogs prior to accepting a bitch for mating
a. ask to inspect her pedigree to see that PA lines are not involved, and
b. If PA lines are involved, satisfy themselves that the owner is complying with the above recommendations.
LIST OF CARRIERS
All the following dogs/bitches should be considered as carriers in order to operate the control scheme effectively.
SECTION A
The following dogs/bitches are proven carriers as defined by the fact that each has produced one or more cases of PA
| DOGS Cassella Chieftan Dallgerry Golden Rambler Donnymoor Good Times Funny Bunny of Felden Esanar Ode to Billy Jo Golden Harvest Hazefield Barbarossa Jason Royal Jomark Ambassador Marbelton Desparate Dan (Ch) Marbelton Lukenorth Mauraine Mr O’Malley Muirham Cherokee Kid Muirham Emporor Napoleon Newlaithe Easy Going Newlaithe Odin Newlaithe Quibbler (Ch) Shiloh Doc Holiday Skelder Red Rogue Tyzack’s Tumbledown Wind Vincel Van Dyke |
BITCHES Abbeygale Lady Nina Braybourne Bold Amber Burford Wild Honey Camsail Carousel Cassandra Shambles Chellbeck Polly Flinders Daltonian Little Gem Detzils Sheba of Almatyne Donnymoor Crazy Momma Inglethorn Gymslip Iron Lady Jordans Hot Chocolate Linkside My Lady Ursula Marbelton Dozy Daphne Flora Dora of Marbelton Marbelton Mademoiselle Marbelton Peepshow Muirham Sheba of Kilmanay Newlaithe Ariadne (Ch) Shebana Barsaba Skelder Fainty Feline Thunderbird Lightning Vincel Charlotte Vincel Cider Honey Wrencliffe Careful Choice of Inglethorn (Ch) Wygold Ship’s Belle Ebony Eyes of Winuwuk |
SECTION B
On the basis of pedigree analysis the following dogs/bitches should also be regarded as PA carriers.
| DOGS Dark Secret of Braybourne Clayva Argonaught (Ch) Dallgerry Gold Bric-a-Brac Eskaidee Cosmic Eskaidee Wor Spuggie Gremlin Jolly Swagman Hazefield Barrister (Ch) Kenadian Rhinestone Cowboy Marbelton Roger the Dodger Muirham Sir Galahad Poldice Bosun Bugalug Poldice Parcival of Felden Scouse Power of Marbelton Donovan of Skelder Summerdale Walk Tall (Ch) Vaneck Jurist Wrencliff Captain Pug Wash |
BITCHES Bainbridge Rayfos Small Talk Camsial Burnt Cinnamon Donnymoor Honky Tonk Woman Donnymoor Satisfaction Gremlin Jolly Stroller Gremlin Libertto Gremlin Walk On Halldors Minuet Halldors Rosamunda Hazefield Best Seller of Newlaithe Hazefield Blue Grass Jonters Giselle Lancars Small Shower of Audee Marbelton Charnvyl Personality Girl Marbelton Rayfos Chatterbox Marbelton Dark ‘n’ Delicious Marbelton Suffragette Too True of Marbelton Marven Marianne Hey Dilly of Newlaithe Newlaithe Vashti Rememarc Miss Moppett Scallywag of Skelder (Ch) Wrencliff Silver Raindrop |
SECTION C
The parents of an historical case with retrospective veterinary diagnosis are as follows:-
| Hazefield Barrister (Ch), see section B |
Tyzack’s Tudor Tilly |
| The following are sires and dams of possible historical cases of PA (lacking veterinary diagnosis) and on this basis could be regarded as carriers: |
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| Scouse Power of Marbelton, see Section B |
Waltham Duskie Maiden Vincel Charlotte Vincel Kerry Dancer Zeebien Amber Gambler |
| Newlaithe Quibbler (Ch) see Section A Summerdale Logic (Ch) |
Starmark Black Eyed Susie Radden Romance |
LIST OF CLEARED DOGS/BITCHES
Examination of the past breeding records of the following dogs/bitches indicates that the probability that any of them is a PA carrier is so small that for the purposes of the control scheme they may be considered clear of PA whether or not there is any implication by pedigree:-
DOGS |
BITCHES
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NORWEGIAN CASES |
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DOGS SECTION A SECTION B Marikarlos Dream Boy |
BITCHES |