USKBTC Health and Genetics Committee
PNA Research & Update
January 14, 2004
Dear Fellow USKBTC Club members: Dr. Gary Johnson, co-primary PNA researcher from the University of Missouri School of Veterinary Medicine, has provided this PNA research update (as of December 31, 2004) for our club. Dr. Johnson gave an excellent presentation for the USKBTC at Montgomery County, and the club is grateful for him taking the time out of his busy schedule to speak to our group. He and Dr. Dennis O’Brien are continuously working on finding the exact location of the PNA genetic mutation.
A linkage test is currently available, and hopefully soon there will be a test for the exact mutuation. Club members interested in donating monies towards this research can do so through the USKBTC Charitable Funds program, which can be found in the report by the Funds committee. We will post updates on the progress of PNA research as things develop.
Thanks to all club members for their continued support.
USKBTC Health and Genetics Committee
Scott Kellogg DVM, Committee Chairman
Dr. Johnson’s letter to the USKBTC H&G Committee is below.
I want you and the Kerry Blue Terrier Club members to know that we at the University of Missouri are continuing our work on PNA. When I spoke at the Kerry Blue Terrier National Specialty in Philadelphia, we had identified the canine chromosome containing the mutant PNA gene and narrowed the search to a twenty million base pair segment of that chromosome which contains approximately 100 genes. Among these hundred or so genes was a gene that caused a similar neurodegenerative disease in people. We had identified a mutation within the canine version of that gene and for a while there, we thought we had found the cause of PNA; however, as we began testing for this mutation, we found that it appeared in some known normal dogs, indicating that this mutation was not the cause of PNA.
Since then we have narrowed the target region to eleven million base pairs containing 41 genes. Thus, we have narrowed the search to about four tenths of one percent of the canine DNA code. The suspect gene is still in the target region, and we are continuing the search for the causative mutation within this gene. Unfortunately, the gene is very large and it isn’t financially feasible for us to sequence the entire gene. Early in 2005 we are planning to employ a new technique which we hope will lead us to the mutation causing the disease. While we continue to look for the mutation, we plan to develop and use what is known as a “linked marker” to evaluate the approximately 200 Kerry Blue Terrier samples sent to us for testing.
Linked markers are not as reliable as the so-called “disease” markers which directly test for mutation; nonetheless, they can be very useful. For instance, a linked marker offered by VetGen was used to greatly reduce the incidence of heritable copper toxicosis in Bedlington Terriers. Our linked marker will consist of a pattern of sequences known as a haplotype in the target region. Dogs with the mutant haplotype on one chromosome are probable carriers of the disease. Dogs that lack the mutant haplotype are considered normal. Our first attempt at a linked marker involved a haplotype region that was too broad and misidentified some dogs. In the next few weeks, we will evaluate a more focused haplotype. Hopefully, this more focused haplotype will provide us with a sufficiently accurate test, and we can provide interim results while we continue to search for the mutation causing the disease.
One reason that research has gone so slow is that we only have samples from four affected Kerry Blue Terriers. Samples from additional affected dogs or their close relatives would be of great help. If you know of any affected dogs or relatives and would like to help, please contact project coordinator Liz Hansen by email at HansenL@missouri.edu, or by phone 573-884-3712. Forms and instructions for sending samples are found on our website, www.CanineGeneticDiseases.net, in the “Ataxia” section.
Gary Johnson, DVM, PhD
USKBTC FULLFILLS INITIAL COMMITMENT TO PNA PROJECT
On December 30 the USKBTC, through its Charitable Funds, sent a check for $7,500 to the University of Missouri in support of Dr. Gary S. Johnson’s on-going research on PNA. As many of you know, the specific marker has not yet been identified.
As a result, Dr. Johnson has requested the remaining $2,500 of the committed $10,000 be retained for one of the AKC/Canine Health Foundation “Acorn” grants. The “Acorn” proposal will be submitted by Dr. Johnson when a linked marker is ready for testing and the funds utilized for DNA testing. Through Dr. Scott Kellogg, Chair of the USKBTC Health and Genetics Committee, on-going dialogue continues with Dr. Johnson on his progress.
Tax deductible donations to the USKBTC’s Charitable Funds (501c3 non-profit status) to support Health and Genetics Research, Rescue and Education may be sent to:
Tom Rogers, CF Treasurer
USKBTC – Charitable Funds, Inc.
317 West Ridge Road
Joliet, IL 60431-4887
Last Updated: 01/14/2005, 10:25 am