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Zdrowie Genetyczne badania nad PRA oraz retinopatią
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Ponieważ forma prcd-PRA nie jest jedyną formą PRA występującą w populacji grzywaczy (istnieją co najmniej 3 formy PRA w tej rasie), prowadzone są badania nad rozpoznaniem kolejnych form/mutacji PRA. Zbierane są próbki materiału genetycznego od psów z rozpoznanym PRA, które są 'genetycznie wolne' od formy prcd-PRA. Badania te prowadzą:
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OptiGen®, LLC (USA)
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Dr. Simon Petersen-Jones
------------------------------------------------------------------------------------------------------------- Short Information in regards to Chinese Crested Dog PRA Research By Dr. Kristina Narfström January 10, 2010
Since approximately 1.5 years I’ve been engaged in PRA research concerning the Chinese Crested Dog (CCD). The background is that many cases of retinal blinding disease have been observed in CCDs in Sweden. Some of the affected dogs have been blood tested in regards to the prcd mutation, responsible for PRA in a number of dog breeds, and has also been found in CCDs affected by retinal blinding disease (see http://www.optigen.com). We have found that many of the cases observed in Sweden have been negative for this mutation even though they have gone blind with a retinal disease process. Through examination of a large number of CCDs in Sweden and smaller groups of CCDs in USA, I have found that we are dealing with more than one problem in the breed in regards to retinal disease. First of all, there are a lot of color variations in the breed and this affects also the retinal appearance, causing color changes that may be difficult to differentiate from early stage PRA. Secondly, there appears to be a “new” type of retinal disease in the breed different from classical PRA. The disease is very slowly progressive and some cases lead to severe visual impairment or blindness. The disorder appears to affect the outermost layer of the retina, not only photoreceptors primarily as in classical PRA. Upon eye examination using indirect ophthalmoscopy, the disease has a somewhat different appearance than PRA of the prcd type. I call this “new” type of retinal problem CCD retinopathy. Thirdly, we also see classical PRA in the breed, in dogs that are positive for the prcd mutation. Through research into the retinal problems of CCDs we will evaluate and study cases that have been diagnosed with PRA or PRA-like disease but that have been blood tested and are negative for the prcd mutation. In collaboration with the crestednetwork.se and the CCD breed club in Sweden, Dr. Tomas Bergstrom and Dr. Leif Andersson, both at the Swedish University of Agricultural Sciences and Uppsala University, and Dr. Gary Johnson and Liz Hansen, both at the University of Missouri, MO, USA, we want to find the gene/mutation for the CCD retinopathy. At the same time the plan is to characterize the disease clinically and using laboratory methods, such as electroretinography (ERG) and morphology (microscopic examination of tissues from affected individuals). In order for us to succeed we would like to obtain blood samples from CCDs that have been diagnosed with retinal blinding disease/PRA but that have been blood tested and are negative for the prcd mutation. For this, fresh blood can be submitted in purple top vials (EDTA), together with a copy of the latest eye examination certificate issued by a board certified veterinary ophthalmologist, and a copy of the pedigree of the affected dog. Initially we will screen for mutations known to cause PRA in other dog breeds, such as the CORD1 mutation. Then, further molecular genetic research will be performed. Address for submission of blood in USA: Animal Molecular Genetics Laboratory, Attention: Liz Hansen University of Missouri –College of Veterinary Medicine 321 Connaway Hall Columbia, MO 65211
Phone: 573 884 3712 e-mail: HansenL@missouri.edu
Thank you for your help!
KRISTINA NARFSTRÖM, DVM, PhD, DipECVO Professor of Ophthalmology University of Missouri-Columbia
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