For The Health of Your Mini...

A new column dedicated to addressing the health concerns of the MBTCA membership.

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GENETICS AND HEALTH COMMITTEE REPORT

I spoke to Liz Hansen and also to Dr. Johnson in late July concerning progress on the ongoing Mini Bull research project at the University of Missouri. There has been no luck as yet in identifying anything in the DNA of luxated dogs to distinguish them from non-luxated or normal dogs. Dr. Johnson has asked the AKC Canine Health Foundation for its approval to continue his grant for another year. However, he is not asking us for any additional funding since he has not as yet made much progress in finding the genetic marker his team is seeking.

The sense I got from speaking with both Liz and Dr. Johnson was that the best hope for furthering our knowledge about lens luxation in Minis is likely to come from studies of lens luxation in the Tibetan Terrier and also from the Sealyham Terrier. For the past several years, the lab at U of Missouri has been working on other hereditary disorders in Tibetan Terriers. Their data bank contains blood samples from hundreds of Tibetans and many extended pedigrees. As you already know, Tibetans also suffer lens luxation, most likely from the terrier gene, which was accidentally added to the Tibetan gene pool when an accidental mating occurred many years ago. The story is that a stray dog thought to be a Tibetan, was declared to be one by a group of breed authorities, and thereby entered into the British stud book. This dog, apparently a very handsome fellow, was widely used and produced numerous equally handsome offspring who were also widely used. When cases of luxation began to appear in the breed, the luxated dogs all seemed to trace back the 'stray Tibetan Terrier'. Since lens luxation is considered a terrier disorder but the Tibetan is not considered a true terrier, it is thought that there must have been infusion of terrier genes somewhere.

In addition to having many animals to work with, the Tibetans are not as closely inbred as are the Mini Bulls. The chances of finding differences between normal and luxated dogs should be greater.

Other good news is the interest in our lens luxation project shown by the Sealyham breeders. Liz told me that in addition to many blood samples, she has an extended family pedigree with numerous luxated Sealys. Perhaps a break will come from this direction as, once again it is probably the same abnormal gene at work in them.

The AKC Canine Health Foundation has asked our club to financially support a new research project which has just been approved. The cost would be $2500 per year for two years. The researcher is focusing on eight breeds, one of which is the Miniature Bull Terrier. A quote from the Lay Abstract accompanying the request reads: 'the majority of disorders affecting purebred dogs have no known counterpart in humans and therefore no candidate gene. However, an indirect test that screens for strong association of a microsatteline DNA marker with a disease phenotype can be incorporated in a simple diagnostic test for carriers of the trait. The ultimate goal of this research is to design marker panels containing a minimum of 300 microsattelite markers covering all the linkage groups on chromosomes of the canine genome. The Veterinary Genetics Laboratory has completed panels containing 100 markers with known map locations. This project will incorporate at least 200 additional markers map locations that will then represent the entire canine genome and allow effective screening for linkage of markers to disease genes."

Today I spoke with Erika Werne, Grants Administrator at the Health Foundation, to find out more about ways in which this project will be different from several other genome mapping projects currently supported by the AKC-CHF. Erika said that this project is significantly different. She is sending me a copy of the complete proposal as submitted and eventually approved. I am interested in reasons why Mini Bulls (and Bull Terriers) are among the eight breeds to be studied.

The following is Dr. Modiano's summary of the talk he gave on cancer genetics and the importance of "Tumor suppressor genes' at the AKC Health Foundation conference last October. Summary