Addison’s Disease in Standard Poodles
An Update by: Cindy Crawley, beauciel Poodles, baltimore, md
Standard Poodle breeders have been waiting more than ten years for a breakthrough in the genetic research on addison’s disease. finally, there is news that scien- tists are a big step closer to that breakthrough.
a collaborative of researchers in the uS and abroad have data that thus far show addison’s disease in Standard Poodles is a polygenic disorder. it seems to have multiple genes involved and seems to be inher- ited more like hip dysplasia rather than as a simple recessive gene as has been previously reported.
dr. Kerstin lindblad-Toh is leading the study. dr. lindblad-Toh is Co-director of the genome Sequenc- ing and analysis Program at miT’s broad institute and a guest Professor in Comparative genomics at her alma mater, the university of uppsala in Sweden. at broad, she leads the mammalian and genome initia- tive. She directed the effort to sequence and analyze the genomes of the mouse, dog, chimpanzee, horse and opossum. She also leads the dog-disease mapping group, which focuses on identifying genes for cancer and autoimmune diseases. her group at broad devel- oped the new technology that has been used to identify several canine disease genes. This is the technique she is currently using to search for the genes involved in addison’s disease in Standard Poodles. dr. lind- blad-Toh is collaborating with dr. ake hedhammar of the Swedish agricultural institute and dr. anita ober- bauer of the university of California at davis, who has been studying addison’s disease in Standard Poodles for years.
in the fall of 2007, dr. gordon lark and dr. Kev- in Chase, of the university of utah’s lark lab, best known among Portugese Water dogs fanciers for the ongoing “georgie Project”, agreed to compare the dna of Standard Poodles with addison’s disease to the dna of Portugese Water dogs similarly affect- ed to see if they had genes in common. dr. Chase also analyzed a database of over 100,000 Standard Poodles, which included health data from the Poodle health registry and a number of other private sources. his analysis indicates a much lower incidence of ad-
The Poodle Papers
dison’s in Standard Poodles than has been previously reported and a much lower frequency of the disease in SP than in PWd.
While Dr. Chase’s finding does not indicate that Addi- son’s disease is not the growing problem that breeders and owners thought it was, it does indicate that with very careful breeding choices, breeders can lower the frequency of this disease in individual lines and in the variety overall.
according to researchers involved in both studies, and based on these new findings, SP breeders should not remove producers of addisonian offspring or siblings of addisonians from their breeding program. With an increasingly shrinking gene pool, breeders will do more harm than good by removing large numbers of dogs than by breeding them selectively and replacing them with a lower risk parent of offspring. Very selec- tive breeding to unrelated dogs improves the chances of breaking up the set of genes that cause the disease. Sires or bitches who have produced addison’s should be bred sparingly and breeders should plan those breedings very carefully until a genetic test is avail- able. until more information is available, breeders should consider dogs that have produced multiple, early onset and severely affected dogs as much higher risk for producing more affected offspring than those that have produced just one out of many litters.
dr. Jerold bell, dVm, of the Tufts university School of Veterinary medicine and occasional speaker at PCa, has described a breeding strategy for polygenic disorders in dogs, using hip dysplasia, certain con- genital heart defects and epilepsy as examples. bell found that in polygenic disorders, the health status of full siblings in addition to the sire and the dam - that is the breadth of the pedigree – provides better insight into choices for breeders rather than the health of the parents, grandparents etc. – that is the depth of the pedigree. (dr. bell’s entire text on this subject, may be accessed at http://www.vin.com/proceedings/Proceed- ings.plx?Cid=TufTSbg2003&Pidq15 &o=generic ).
There is still work to be done. blood and serum sam- ples are needed by uCdavis and the lark lab from both addison’s-affected dogs and from older (age 8 or more) healthy unaffected dogs. anyone interested in
participating in the ongoing research at the lark lab cont. on page 16