| Marilyn Brotherton, Aisling Kennel, Perm. Reg.
Written January, 1999 |
| In 1957 I looked after a 4-year-old boy named Brian, as his nurse. He was a perfect looking
child, but totally unaware of his surroundings, unable to swallow, or to move a muscle. He had
Tay-Sach's disease, diagnosed when he was six months old - a progressive neurological disease
which slowly destroyed his brain cells. This genetically inherited disease is peculiar to Jewish
people of the Ashkenazi descent line, a few French-Canadians, and some Louisiana Creoles. The
victims all die by the time they are five years old. One in 30 Jewish people in America is a
carrier for this devastating & fatal gene.
I spent a great deal of time with his family, as we all waited for Brian's inevitable death. Not only was his family suffering through the 4 - 5 year trauma of his disease, but they were also faced with the knowledge from the geneticist that mom had a 1 in 4 risk of producing another "Brian" if she got pregnant again. |
| Twenty years later, while nursing at the University Health Clinic, a blood test became available to detect carriers for Tay-Sach's Disease. The Health Service staff did an informational blitz, and tested a number of people that year - many were declared free of the gene, but several were classed as carriers. |
| One young woman stands out in my mind, and I'll call her Mona - a very intelligent young woman, about to graduate with her Masters Degree in mathematics. Mona refused to have the test. She was afraid to find out that she might be a carrier. All the information, and all the logistical statistics meant nothing to her. The potential emotional pain of watching her own child die, day by day for five long years had no impact. Mona was determined to "take her chances," and thus risk producing her own "Brian" and if not in her lifetime, perhaps in her granddaughter's lifetime. I told her about my memories of Brian and his family, but that also held no meaning. You see, they were people she didn't know, and didn't really care about, and besides, no one in her family had died of this disease. |
| So what's this got to do with us Kerry Blue Terrier Fanciers and breeders? |
| Just about everything! |
| ** | We too have a genetically inherited neurological disease in our chosen race of canines -- PNA.- Progressive Neuronal Abiotrophy. Information is available from the USKBTC & also at http://www.kerryblues.org. |
| ** | The outcome for the victims of this disease is also inevitable death. |
| ** | We have specific identified probable genetic sources, as noted in the PNA information booklet from the USKBT - see statement 6, (Ch.Tailteann's Jim's Showoff & Ch. Bhoy's Brigid of the Bog) as well as other suspect sources because of the in-depth work of Dr. de Lahunta at Cornell University and later, of other professional & knowledgeable individuals. |
| ** | We have dedicated breeders who have reported producing diseased pups, along with their pedigrees for us to study. |
| ** | We also have individuals who do not want to know, do not want to tell, and do not wish to be involved in finding a solution - a D.N.A. marker. They, like Mona, will "take their chances." |
| ** | We now have the possibility to have a test created to prove or disprove carrier status, thanks to modern technological advances |
| Some Kerry Blue Terrier breeders seem to be governed by fear, apathy or denial of reality, but many breeders are simply unaware of the disease and the significance of a pedigree. They are also unaware of the emotional pain they will undergo as producers of a defective puppy, as they watch it deteriorate before their eyes, or have to deal with distraught puppy owners who are overwhelmed by the unforgiving diagnosis of Progressive Neuronal Abiotrophy.. |
| The Kerry Blue Terrier Club of England, in their Handbook of 1977, stated in part that "What we have to guard against is the day when the line disappears from the pedigrees and the breeders will breed, and find themselves with litters of fatally diseased puppies and the whole horrible business will start all over again and could destroy the breed completely." |
| I fear that this expressed concern in 1977 is precisely what is happening to us in North America in 1998. |
| I am including below, also in italics, an excerpt from a long, but very good article, which is available in its entirety, on the Internet at www.beardiehealth/Genes-Bell.htm |
| IDENTIFYING AND CONTROLLING DEFECTIVE GENES |
| Knowing How is the First Step in Tackling the Problem |
|
Jerold S. Bell, DVM |
| ** Once a genetic basis for a disorder is established, breeders
need to put emotions and accusations behind and deal with the
problem of control.
** No one who loves a breed wishes to produce defective dogs or propagate deleterious genes. ** No one can create a defective gene through breeding practices. ** No matter how long or through how many dogs defective genes have been spread, concerned breeders must start from the point of recognition of the defect and work together toward the improvement of the genetic health of the breed.. |
| VetGen, in Ann Arbor, Michigan, is discovering DNA markers for inherited defects in dogs. Their research is mainly targeted at popular breeds who have high numbers of common defects. The Kerry Blue Terrier is not included in this group. However, VetGen has established a DNA marker for Copper Toxicosis in the Bedlington Terrier, because of the impact this gene has on a breed with a small gene pool. |
| Surely the Kerry Blue and the PNA gene falls into this category, by virtue of our small numbers as well. |
| Let us, through our National Executive, take the steps now to approach researchers on this fatal genetic flaw that threatens our breed, and support them with the funding, dogs and affected pups. |
| It seems to me that we must take action now, and the National Club must lead the way with our support, encouragement, and financial assistance. Taking steps does not mean setting up one more committee to study the problem. We have the committee and the studies. We need ACTION. |
|
"Blueprints" & "BlueNotes" should be reminding us in each issue about this disease, instead of ignoring it. Education is an important key to containment of the disease |
| In the meantime, until this test is available, there is one very important thing we can all do. |
| Each individual breeder can work out pedigrees with information currently available and choose the mates wisely and carefully, specifically to reduce the risk of PNA. Pedigree research is a time-consuming task, but a vital one. If you discover that you have a bitch who carries several crosses back to the known original source of PNA in America, choose a mate from lines who are NOT connected to that source. It's immaterial that the mate selected is a great-winning dog - he just must be healthy and typey. You will immediately reduce the puppy genetic load by 50%. This does not provide you with complete protection from producing pups with the disease, but it certainly puts a far less risk to the litter. |
| There is a definite lack of easy access to the information to work back a pedigree as I have done, but the data and help are available if you are persistent. You should contact the parent Club for assistance with it, as well as breeders who have maintained pedigree information. |
| We must be able to understand what is happening in a blood line in order to take the remedial steps to decrease the genetic load on a litter, until we have a methodology to make the appropriate genetic choices for matings. This could be soon, if we are united in a demand for it. |
| There are many clear dogs who also trace back to the identified American & Canadian originators of PNA, but they cannot be claimed as being clear without testing and thus are held unfairly under a cloud of suspicion. |
| We need to correct that situation. It is unfair to the breeders who produced them, to those who own them, and to the Kerry Blue Terrier breed itself. |
| We desperately need to have these identified clear dogs in the gene pool. |
| The USKBTC. has correspondence dating back to the mid-70's from concerned breeders
regarding the potential spread for this genetic disease if concrete steps were not taken to control
the infiltration of PNA at that time. The National Club published the information on PNA in
1975, but very little else has been done since then to help minimize the impact of this disease.
This attitude of apparent indifference has promoted the impression that we should be ashamed to say we have a problem, or that we should ignore it. In my opinion, we are no further ahead in solving the puzzle with any current solution than we were in 1975. In fact, we have regressed, as many pedigrees of today are riddled with potential carriers for disaster in comparison with pedigrees from the early 1970's. |
| The Kerry Blue Terrier breed is very small in numbers in North America, and just got smaller with the recent tragic death of two pups, and the black cloud of suspicion that now hangs over the siblings, the 2 parents and the 4 grandparents, not all of whom are necessarily carrying the defective gene. |
| I studied the pedigree of puppies born in 1998 to define what has happened over the years, and what is being repeated in many pedigrees of today, without breeders being aware of, or understanding what a vast, insidious problem they are dealing with. I traced these pups back through 8 generations of progeny from the original named suspect source. Details can be found at the end of this article. |
| Statistically, through the past 8 generations, the genetic load for PNA on these pups went from a combined total of 6.17% potential carriers in the 8th generation to 200% in this generation. |
| The combined sire & dam number of potential carriers in the 8th generation was 16 out of 1,020 dogs, but in the current 1st generation it has risen to 141 dogs with many of the dogs in the pedigree carrying possibly doubled-up influences. There are 9 times more potential carriers in only 35 years of breeding. The percentage risk of PNA for this litter is more than 30 times what it was in the early 70's. These numbers clearly show how the incidence for affected pups was inevitable, and innumerable other planned matings by other breeders will have pedigrees in the same risk area if examined in depth! |
| We can't afford ANY more time to pass with inaction. Our breed is in a dangerous situation. |
| What can or should we do, starting now? |
| There needs to be a multi-faceted approach to this complex puzzle, and the solution is going to be dependent on us working together co-operatively. |
| We must first of all acknowledge that this genetic problem exists! |
| Too many new breeders (as well as owners) are totally unaware of this inherited condition. |
| These future breeders originally come to us for their first Kerry pup. This is when we should be telling them about all the potential genetic problems in the breed - hip dysplasia, bleeding disorders, and Progressive Neuronal Abiotrophy. |
| Even if we as breeders feel that these are NOT problems in our particular strain of Kerries we still should not be silent. Information is the beginning of the open-ness and acknowledgment that needs to be fostered. |
| We must all become better informed about the disease and basic genetics. We can't "bury" a recessive gene. It will always be there in the dog, regardless of when it was last expressed. All we can do is hopefully reduce the incidence by selective mating. |
| Request and read a copy of the only available definitive work on PNA in Kerry Blue Terriers, published in 1975 by the USKBTC. If you don't understand the information in it ask someone who can explain it to you. |
| Both the Canadian and the American National Clubs must assume a greater responsibility in the area of education and up to date information. As breeders we are entitled to that information. |
| We need to learn to talk openly with each other about this potentially disastrous disease. |
| Many Kerry Blue Terrier breeders are at risk right now of producing an affected puppy. The "whispering" and "finger-pointing" campaigns that have gone on in the past needs to stop. They have prevented advances in knowledge and exchange of information and have forced the disease underground. |
| PNA has become a "shame-based" condition which is complete nonsense. |
| Dogs and people as well as every living entity has a built-in supply of bad genes which were not originally infused by breeders. Our breeding decisions however, in many instances, have resulted in the proliferation of genetic "loads" or increased risks of hereditary defects. |
| We need to learn to "read" a pedigree. |
| Many breeders point with pride (deservedly so) to all the champions in that pedigree but a pedigree is much more than the recording of champions. |
| It is a history of the puppy whose name appears at the top. What dog combinations in that pedigree produced correct colour, and which ones produced coats that didn't turn? Which combinations produced bad bites, or cleft palates? What dog produced soft temperaments? Where did the high tailsets come from - the tiny ears, the monorchids? Oh, yes, a pedigree is much more than a history of show ring success! |
| Open-ness leads others to learning and avoiding repeating similar mistakes. |
| Too many persons have suffered persecution and scorn because a dog they produced became ill. They deserved our support and gratitude for speaking up and supplying the pups to the researchers. |
| I trust that in the future these actions will not re-occur - that we have moved beyond such behaviour. |
| We need these sick puppies to help us solve the mystery of PNA. |
| We need the breeders of these puppies to help the researchers and to educate us. |
| We must be united to solve the mystery of PNA - to develop a DNA test for carrier status. |
| The members - breeders and owners alike - are the backbone of the National Kerry Blue Terrier Clubs. When we, in numbers, direct our Club executive to take positive steps on this issue, I believe they will. |
| If we accept the status quo, nothing will be accomplished, and more pups will be euthanized, more breeders will be confused and devastated and more owners will be heart-broken and the breed will get sicker. |
| Yes, some of our dogs may prove to be carriers, and other decisions then have to be made, but in the long run, there will be one less unknown inherited gene for us to be concerned about. |
| We breeders are only temporary custodians of the breed. What we do to-day in our breeding program will impact the breed forever in the future. |
| Statistics for the COMBINED potential carriers in this one pedigree |
| which produced PNA puppies in 1998 |
| 1998 Litter | gen 1 | gen.2 | gen.3 | gen.4 | gen.5 | gen.6 | gen.7 | gen.8 | Totals |
| # of potential carrier dogs : # of dogs in pedigree | 4 : 4 | 8 : 8 | 13 : 16 | 20 : 32 | 25 : 64 | 27 :128 | 28 : 256 | 16 : 512 | 141/1020 |
| Calculated potential risk factor % | 200% | 200 % | 162.5 % | 125.0% | 78.05% | 42.12 % | 21.18 % | 16.8% |
| The more specific numbers for the sire and dam follow further on in the article. |
| There was a total of 141 potential carrier dogs for PNA in the 1020 dogs behind these affected puppies. |
| The increase in percentages for potential carriers went from 6.1% to 200% in just 8 generations which happened over only 25 years. |
| By contrast, statistics for a litter of PNA puppies in 1974 had a combined total of 12 potential carriers in the 1020 dogs behind it with a percentage risk of 150% in the 1st generation. |
| 1974 Litter | gen 1 | gen.2 | gen.3 | gen.4 | gen.5 | gen.6 | gen.7 | gen.8 | Totals |
| # of potential carrier dogs : # of dogs in pedigree | 3 : 4 | 4 : 8 | 3 : 16 | 2 : 32 | 0 : 64 | 0 : 128 | 0 : 256 | 0 :512 | 12/1020 |
| Calculated potential risk factor % | 150% | 100% | 37.5% | 12.5% | 0% | 0% | 0% | 0% |
| PNA Litter - 1998 | gen 1 | gen.2 | gen.3 | gen.4 | gen.5 | gen.6 | gen.7 | gen.8 | Totals |
| Sire - Calculated potential risk factor % | 100% | 100% | 87.5% | 68.75% | 46.8% | 26.5% | 14.0% | 5% | |
| # of potential carrier dogs : # of dogs in pedigree | 2 : 2 | 4 : 4 | 7 : 8 | 11 : 16 | 15 : 32 | 17 : 64 | 18 : 128
includes 6 unknown status |
13 : 256
includes 37 unknown status |
87 : 1020 |
| Dam - Calculated potential risk factor % | 100% | 100% | 75% | 56.25% | 31.25% | 15.62% | 7.18% | 1.17% | |
| # of potential carrier dogs : # of dogs in pedigree | 2 : 2 | 4 : 4 | 6 : 8 | 9 : 16 | 10 : 32 | 10 : 64
includes 4 unknown status |
10 : 128
includes 14 unknown status |
3 : 256
includes 43 unknown status |
54:1020 |
| Combined Potential Risk Factor Percent 200% | 200% | 200% | 162.5% | 125 % | 78.05% | 42.12% | 21.18% | 6.17% | |
| Combined Potential Carrier Dogs | 4:4 | 8:8 | 13:16 | 20:32 | 25 : 64 | 27: 128 | 28 : 256 | 16 : 512 |
| PNA Litter 1974 | gen 1 | gen.2 | gen.3 | gen.4 | gen.5 | gen.6 | gen.7 | gen.8 | Totals |
| Sire - Calculated potential risk factor % | 50% | 25% | 0% | 0% | 0% | 0% | 0 % | 0% | |
| # of potential carrier dogs : # of dogs in pedigree | 1 : 2
includes 1 unknown status |
1 : 4
includes 2 unknown status |
0 : 8
includes 2 unknown status |
0 : 16
includes 2 unknown status |
0 : 32
includes 3 unknown status |
0 : 64 | 0 : 128 | 0 : 256 | 2 : 1020 |
| Dam - Calculated potential risk factor % | 100% | 75% | 37.5% | 12.5% | 0% | 0% | 0% | 0% | |
| # of potential carrier dogs : # of dogs in pedigree | 2 : 2 | 3 : 4 | 3 : 8 | 2 : 16 | 0 : 32 | 0 : 64 | 0 : 128 | 0 : 256 | 10 : 1020 |
| Combined Potential Risk Factor Percent | 150% | 100% | 37.5% | 12.5% | 0 % | 0 % | 0 % | 0 % | 0 % |
| Combined Potential Carrier Dogs | 3 :4 | 4 :8 | 3 :16 | 2 :32 | 0 :64 | 0:128 | 0:256 | 0:512 |
Canine Reproduction