Dog gPRA

Diagnostics

PRA in Weimaraners -  (validated DNA test now available)

Canine PRA (progressive retinal atrophy) is caused by different genetic changes, like the related inherited eye disease Retinitis pigmentosa in man. Both disorders are characterized by similar symptoms in dogs and humans, initial night blindness, then a reduction in the visual field leading to tunnel vision and finally blindness. Depending on the genetic defect, the retinal changes appear sooner or later during life, albeit mostly in later ages. During the last 15 years, we have investigated different PRA forms in various dog breeds.

Several mature Weimaraners of a certain litter in Germany were  investigated by the ophthalmological specialists of the DOK (DOK = Dortmunder Kreis; Gesellschaft für Diagnostik genetisch bedingter Augenerkrankungen). The suspicion of PRA has been medically confirmed by ophthalmologists. Hence, we started genetic investigations immediately using DNA from blood samples of several Weimaraners that had been previously submitted to the DNA biobank. Initially, we screened several of those genes that cause PRA in many instances as well as mitochondrial DNA (mitochondria ≈ „powerhouses of the cells“). No peculiarities i.e. mutations were encountered in all of these DNA sections. In parallel, we investigated the DNAs of two affected Weimaraners (in comparison with two healthy dogs) with respect to all of those genomic regions, which code for the production of proteins, a so-called exome analysis. In consequence, in two PRA-affected Weimaraners and later, also in several additional grey dogs, we identified a common genetic defect, a mutation in a given gene. This mutation happened in a gene that has been identified as causing Retinitis pigmentosa in man. As expected, the mutation has not been observed in many Weimaraners from different lines with normal eye sight. The mutation is rather complex, so that we had to establish a simple cost-effective DNA test from scratch. The test may be ordered starting on November 11th, 2015. The availability of the test also allows for screening of very young and (still) healthy dogs and confirms or rejects, respectively, the presence of the PRA mutation in Weimaraners.

By using the available DNA testing, also with regard to breeding strategies, precise conclusions may be drawn now, and the PRA mutation may be eradicated from the respective Weimaraner lines. The president of the German Weimaraner Klub e.V. is constantly informed about any new developments concerning PRA test results. Experimental therapies (e.g. using biologicals like CNTF and/or gene therapy, respectively) have been tried abroad with differential success.

For additional information please contact:  joerg.t.epplen@rub.de  

Bochum, 17.11.2015                                                           Prof. Jörg T. Epplen and co-workers


Link for submission of blood samples                  

Genetic Diagnostics Weimaraner

DNA Biobank order form Weimaraner

pricing for mutation / DNA tests 60.- €
including DNA biobank deposit            90.- €
taken from an existing DNA sample  in the biobank 50.- €

DNAs are tested whenever several EDTA blood samples or orders for tests have been received, respectively. Upon completion of the procedure, official DNA expertise is forwarded to the customer immediately; a copy of the test results will also be sent to the German Weimaraner-Klub e.V.

Direct gene diagnosis possible for gPRA in Sloughi dogs

We are offering direct gene diagnostics for gPRA, which is transmitted autosomal recessively in Sloughi dogs. Since the mutation is directly demonstrable by PCR-based tests, the diagnostic certainty is virtually 100%. For breeding purposes heterozygous individuals (asymptomatic gene carriers) can be distinguished reliably from normal (homozygous) genotypes and from affected animals (homozygously mutant). For further details on the discovered mutation see Dekomien et al., 2000 in the sientific journal Cytogenetics and cell genetics.

For ordering of the DNA test (€ 56.- per case) see the attached sheet.

Genetic Diagnostics Sloughi

Direct gene diagnosis possible for gPRA in Schapendoes dogs

Genetic linkage analyses had identified a marker linked to the gPRA locus for Schapendoes dogs (Lippmann et al., 2007). One allele of this marker generates information about the gPRA status of the analysed Schapendoes. Meanwhile, we identified the gPRA causative mutation in a candidate gene of the marker linked region and established a direct mutation test since 1st October 2008. This test (€ 66.- per case) analyses the mutation directly in the gene which is homozygous in affected Schapendoes dogs.

Because of the distance between diagnostic marker and the identified mutation of about 1.6 Mb there is a small theoretical chance for false negative, respectively, positive results in fact of recombination events. In the Schapendoes breed we identified recombination events between marker and mutation in ?1% of all analysed dogs whereby only the b allele is concerned. Thus, we recommend still to order the direct mutation test for all those Schapendoes dogs which had been diagnosed at least with one b allele by the indirect marker test.

Therefore, it is sufficient for Schapendoes owners with indirectly tested dogs to send the order form [PDF] for the direct DNA test. The results will be sent back to the denoted address together with an invoice of 30.- €. (The shipping of further blood samples and a copy of the pedigree is not required for Schapendoes dogs which had already been tested by the indirect marker test.)

Genetic Diagnostics Schapendoes

Molecular genetic risk test for gPRA in Irish Glen of Imaal Terrier available!

After 3 years of intense research, we have identified a mutation in the genome of many Glen of Imaal Terriers, that – in homozygous state – is closely associated with gPRA (Kropatsch et al. 2010). The age of gPRA onset in Glens appears quite variable. The price (€ 70) includes DNA preparation, typing and expertise to be delivered to the owner per mail. For ordering of the risk test see the attached sheet.

Genetic Diagnostics Glen of Imaal Terrier